lcd monitor repair tieng viet unencrypted

Y BAN NHN DN THNH PH H CH MINH TRNG CAO NG GIAO THNG VN TI NGNH SA CHA MY TNH

bi np cui kha

dch t E-book ting Anh "LCD Monitor Repair" ca Jestine Yong

(cm n thy V Ph Cng gi ) Ngi dch: Bi Nam Minh Anh E-mail:[email protected] Mn: Mn Hnh My Tnh Lp: VT1-07A (k chiu) Kha: 2007-2009

h 2009

PDF created with pdfFactory Pro trial version www.pdffactory.com

Bn ang c E-book ting Vit Sa Mn Hnh LCD dch t E-book ting Anh LCD Monitor Repair download min ph trn lqv77 (cm n anhVinh chia s). T trang 2 ti 180 l dch theo Jestine Yong (308 hnh minh ha), mi ch in nghing v cc trang cn li l tm hiu ca ngi dch. Vic dch sai mt s t chuyn mn l khng th trnh khi: cng mt t power nhng lc n l cng sut (power cap, power IC) lc n l ngun (power FET). Sch dch c i ch kh hiu v c th bn s khng bit mnh ang c g mong bn thng cm cho. qu trnh dch sang ting Vit c tham kho l thuyt Mn Hnh My Tnh ngnh Sa Cha My Tnh h TH 2 nm trng C Giao Thng Vn Ti (trng TH Giao Thng Cng Chnh c) cc website k thut vin LE QUANG VINH hc ngh trc tuyn cc website dch t ng trc tuyn min ph ca LC VIT: http://www.vietgle.vn/dich/Default.aspx?tab=dtt&tabc=mt&type= VDICT: http://vdict.com/?autotranslation (c sn GOOGLE TRANSLATE) v cc thnh vin nhit tnh ca box hi - p thuc BAMBOO TRA T


Sa Mn Hnh LCD

Tc gi: Jestine Yong http://www.ElectronicRepairGuide.com http://www.TestingElectronicComponents.com http://www.FindBurntResistorValue.com http://www.JestineYong.com


Bn khng th cho min ph E-book ny. Bn khng c quyn phn phi li E-book ny. Quyn tc gi@mi tc quyn u c bo lu Cnh bo! y l ti liu c bn quyn; khng ni dung no trong y c sao chp hoc pht tn di bt c hnh thc no, bao gm hnh nh, bi v, hoc pht tn bng thit b lu tr m khng c s cho php km ngy thng v ch k ca tc gi. Bn khng th chnh sa, thay i, hoc lm mi li ti liu ny di bt c cch thc no. Jestine Yong c y quyn trc lut bo v s hu tr tu bao gm ni dung, tng trong ti liu ny. Hy thc rng Ebay tch cc hp tc trong vic kha ti khon ngi vi phm bn quyn v h tr truy bt hp php vic vi phm. Nhng iu cn bit v php l Bn c c cnh bo r cn nhc v tip nhn v trnh cc nguy c c th. E-book ny ch dnh cho mc ch thng tin v tc gi khng c bt c trch nhim v ngha v no vi gi tr ca thng tin ny. Mi c gng c thc hin kim chng thng tin c cung cp y, tc gi khng chu bt c trch nhim no v chu ng mt mt, tn hi, li, khng chnh xc, thiu st hoc phin phc xy ra do thng tin ny bi bt c ai. Phn ln cc th thut v b quyt trnh by ch nn c thc hin bi cc k s/k thut vin in t c kh nng thch hp. Hy cn thn bi thit b in t c th nguy him khi tho ra. Bt c s coi thng c hiu no$ v chnh sch, con ngi hoc t chc c th u khng c ch . Nu bn c thng tin lin quan ti vic bn li hoc sao chp E-book ny bt hp php, vui lng bo cho [email protected].

$

tc l nu c bt c s coi thng no trong t ng th l ngoi ch ca tc gi


Li tng

Quyn sch ny xin c tng v Michelle cng cc con Noah v Hannah yu qu ca ti, ng s William Hor, v xinh ca anh y Stephanie v con gi h Naomi


Ni dung1. Thng hiu cng ngh hin th tinh th lng (LCD) --------------------------------------- 7 2. Tng quan cc mch mn hnh LCD ----------------------------------------------------------17 3. S khi mn hnh LCD--------------------------------------------------------------------------19 4. Thng hiu bo cp ngun --------------------------------------------------------------------------20 5. Thng hiu mainboard/bo AD --------------------------------------------------------------------26 6. Thng hiu bo cao p --------------------------------------------------------------------------------30 7. Thng hiu mch khi ng-----------------------------------------------------------------------40 8. Thng hiu backlight (n)-------------------------------------------------------------------------44 9. Thng hiu bng LCD--------------------------------------------------------------------------------53 10. Ch bo tr hng mn hnh LCD ------------------------------------------------------------57 11. Khc bit gia plasma v LCD -------------------------------------------------------------------60 12. Dng c v thit b o --------------------------------------------------------------------------------62 13. B quyt m np mn hnh LCD -----------------------------------------------------------------66 14. Thng hiu m in tr dn v kim tra -----------------------------------------------------70 15. Thng hiu m t dn v kim tra --------------------------------------------------------------75 16. Thng hiu m transistor v diode dn v kim tra -------------------------------------80 17. M IC in hnh mn hnh LCD ------------------------------------------------------------------84 18. ng dng chnh lu diode Schottky v kim tra ------------------------------------------87 19. im nh tc v cht mn hnh LCD -------------------------------------------------------93 20. Bng LCD b nt ---------------------------------------------------------------------------------------96


21. im o in p chun mn hnh LCD -------------------------------------------------------99 22. im o dng sng chun mn hnh LCD ------------------------------------------------ 110 23. Trc trc mu mn hnh LCD ---------------------------------------------------------------- 119 24. Vn hnh trng mn hnh LCD ---------------------------------------------------------- 124 25. Mt ln sng dc mn hnh LCD Philips 170C ------------------------------------------ 127 26. Mt ln sng ngang mn hnh LCD ---------------------------------------------------------- 131 27. Cch sa adapter ngun mn hnh LCD -------------------------------------------------- 133 28. Cch sa vn mt ngun mn hnh LCD Dell E151FP ------------------------- 141 29. Cch sa vn mt hnh mn hnh LCD Dell E152Fpb--------------------------- 146 30. Cch sa vn t tt mn hnh LCD Dell E153Fpc -------------------------------- 150 31. Cch sa vn nhp ngun mn hnh LCD Dell E173FPB ---------------------- 153 32. Cch sa vn mt ngun chp chn my Acer AL511 ------------------------- 157 33. Cch sa vn mt hnh mn hnh LCD Acer FP558 ----------------------------- 159 34. Cch sa vn sc ngang trng en mn hnh LCD Samsung 151V ------ 163 35. Cch sa vn hnh m mn hnh LCD Samsung 153V------------------------- 166 36. Cch sa vn mt ngun mn hnh LCD Samsung 153V --------------------- 170 37. Cch sa vn mt ngun mn hnh LCD Samsung 510BN------------------- 173 38. Cch sa vn OSD mn hnh LCD Samsung 713N------------------------------ 176 39. Ngun ngh ----------------------------------------------------------------------------------------- 179 40. Phn kt ---------------------------------------------------------------------------------------180


Thng hiu cng ngh hin th tinh th lng (LCD)

Mn hnh LCD Gii thiu LCD hay mn hnh vi tnh bng phng l cng hin to ln nht v gn y nht trong cng nghip my tnh bn. Chng c dng trn th trng my xch tay t nhiu nm, nhng s pht trin gn y tng hiu sut v kch c cng lc vi ct gim chi ph gip chng tn ti c trn th trng my bn. Mn hnh LCD nh k, siu mng v t hao in hn mn hnh CRT. Tinh th lng l g v n hot ng nh th no? Tinh th lng c pht hin bi nh sinh vt hc Fredreich Rheinizer ngi o nm 1888. Tinh th lng l vt cht hu c l thng bi n khng phi cht rn cng khng l cht lng. iu c ngha d trng thi l cht lng, tinh th lng li mang cu trc ca phn t tinh th tng t cht rn. Tinh th lng l cc phn t hnh que m chng c th c sp thnh hng mt cch chnh xc khi vo vng in trng. Do l cht lng, chng c th chy theo quanh cc kha rnh nh v c th thay i v tr ca chng ty theo in p t vo. Khi sp thnh hng hp l, tinh th lng cho php nh sng i qua to thnh nh mong mun.


Cc phn t sp Khi tip xc vi b Cc phn t sp xp theo kiu cch mt c khe p hng song song c trt t lng lo (lp thng hng) dc theo cc khe Cc phn t tinh th trng thi t nhin Mn hnh LCD gm su lp: nh sng nn (backlight), knh phn cc (polarizer), knh TFT (TFT glass), dung dch tinh th lng (liquid crystal solution), knh lc mu/b lc mu (colour filter/colour filter glass) v knh phn cc th hai.

nh ngun thuc in T Samsung Ngun sng hunh quang, cn gi l backlight, to thnh lt ct sau cui (hnh). nh sng c chiu t pha sau cc bng. nh sng ny xuyn qua knh phn cc th nht. nh sng c phn cc sau xuyn qua lp cha hng ngn git tinh th lng c dn hng trong mt ch cha nh xu gi l . Cc , ln lt, c dn thnh hng khp mn nh, ba to thnh mt im nh$ (pixel, im nh nht c th nhn r trn mn hnh), in dn quanh l LCD to ra in trng lm phn t tinh th xon li, phn t tinh th sp nh sng thnh hng bng knh lc phn cc th hai v cho php nh sng xuyn qua. Mi tinh th hoc cho php nh sng xuyn qua hoc chn nh sng. S nh hnh cc tinh th to thnh nh.

Mi im nh rng khong 300m trong c ba im mu, mi im mu c mt transistor iu khin. D liu nh s c a ln lt vo cc G (cc cng - gate) iu khin cho cc transistor ny dn to ra t trng lm i hng cc tinh th lng. /*l thuyt Mn Hnh My Tnh*/

$


Phn loi LCD Mn hnh mu LCD c hai loi c bn: ma trn th ng v ma trn tch cc.

im nh

im ()

im () li

im nh li

mn nh LCD

Vi bng LCD mu, mi im nh to ra bi ba tinh th lng. Cc im nh thc s khng sinh mu m bn thy. l nh sng trng (backlight) xuyn qua mi im nh c lc to thnh mu mong mun. Knh pha trc mi im () mu , xanh l v xanh dng th c ph cht lc mu. nh sng xuyn qua cc lc mu to ra mu nh bn thy trn LCD. Mi hay im nh con c th c ch nh a ch mt cch ring l bng mt in p iu khin. V d, mn nh ca mn hnh LCD 15 c phn gii 1024 x 768 s c 2.359.296 im nh con (1024 x 768 x 3). Thnh thong c ch gi dng in n mt hay nhiu im nh gp tht bi. Trng hp bn s thy mt ti hn ( li) hay im nh li. c thm v im nh li chng im nh tc v cht mn hnh LCD.


LCD ma trn th ng

ni t ti yIC li LCD

ct in p dng t ti y

hng v ct giao nhau ti im nhc ch nh nh sng xuyn qua v xut hin mu xanh

hng

cch thc mt LCD ma trn th ng lm vic

Mn hnh LCD ma trn th ng s dng li in$ n gin cp cho mt im nh c th trn mn hnh. To ra li in l c mt qu trnh! N bt u vi hai lp knh gi l nn, mt cho ct v mt cho hng, c lm t cht liu truyn dn trong sut. Hng hay ct c ni vo cc mch tch hp iu khin khi in tch c gi ti mt ct hay hng c th. Cht tinh th lng c kp gia hai nn knh v mt mng phn cc c thm vo pha ngoi mi nn. bt mt im nh, mch tch hp gi in tch ti ct ng ca mt nn v im ni t c kch hot trn hng ng ca nn kia. Hng v ct giao nhau ti im nh c ch nh v n cung cp in p dui tinh th lng ti im nh . V d, nu im hng 0, ct 0 l mu , th cc im mu xanh l v xanh dng phi bt ti im nh chn nh sng trng xuyn qua tr b lc mu . nh sng trng hnh trnh xuyn qua b lc mu trong knh pha trc ni nh sng hin mu . Khi cc im mu , xanh l v xanh dng u bt, mi nh sng b chn v im nh xut hin mu en. Nu c ba im u tt, mi nh sng xuyn qua v im nh xut hin mu trng. Cng c nhng bt tin d tnh n gin ca h thng ma trn th ng th tt. Th nht, thi gian p ng chm. Thi gian p ng lin quan ti kh nng lm ti (refresh rate) nh hin th ca LCD. Cch d nht quan st thi gian p ng chm vi LCD ma trn th ng l cho con tr chut di chuyn nhanh t cnh ny sang cnh khc trn mn nh. Bn s nhn thy mt lot bng ma theo sau con tr. Thi gian cp nht chm nh th khin mn hnh th ng tr thnh s la chn ngho nn i vi cc thao tc ha nhanh (nh game), hot nh v video ng. Th hai, h s tng phn thp thng cho kt qu l nh bay mu hoc sng m. Th ba, gc nhn i vi LCD ma trn th ng mu cng khng rng, vo khong 45 . iu c ngha tm nhn r nht ca mn hnh l phi nhn thng vo.Cc ct in cc mu , xanh l v xanh dng cho mi im nh c t knh pha trc cn knh pha sau s t mt hng in cc do chng ta c th thy s lng ct in cc nhiu gp ba ln s lng hng in cc. /*l thuyt Mn Hnh My Tnh*/$


Cng ngh ma trn tch cc hay TFT (Thin Film Transistor)

ct

im nh hng

mt im ()

transistor mng mng cch thc LCD ma trn tch cc lm vic

TFT vit tt ca transistor mng mng (cng l ma trn tch cc) cho nh mu nt nh mn hnh CRT truyn thng. V c bn, TFT l cc transistor v t ngt/m nh xu. Ba phn t cp ngun sng mu , xanh l v xanh dng cho mi im nh m mt bn quan st c. Chng c sp trong mt ma trn trn mt nn knh. n mt im nh c th, hng thch hp c bt, v sau mt in tch c gi xung ct ng. Bi mi hng khc m ct giao vi chng c tt, ch c t ti im nh c ch nh mi nhn in tch. T in c th gi c in tch cho ti chu k lm mi k tip. V nu chng ta cn thn kim sot mc in p t vo tinh th, chng ta c th dui chng ra ch cho php mt s nh sng xuyn qua. iu ny c ngha l o mch xy ra ngay lc ang bt hoc tt nh sng trng v kt qu l thi gian p ng nhanh hn, v t nhiu xuyn m$gia cc hn. Khi cc phn t mu , xanh l v xanh dng u tt, nh sng trng chiu xuyn ba phn t v im nh xut hin mu trng. Nu cc phn t mu , xanh l v xanh dng u bt, mi nh sng b chn, v im nh xut hin mu en.

Nhiu sinh ra bi cc ng cp truyn t qu gn nhau. i khi bn nghe c cc xuyn m trn in thoi. Khi lin lc in thoi ng di, vic nghe thy xen ln cc ting ni khc hoc ton b cuc ni chuyn khc trn nn cuc ni chuyn ca bn, khng phi l him gp. Nhiu xuyn m gy cn tr cho nhng qu trnh truyn d liu khng li. /*t in tin hc LC VIT 2002*/

$


mn nh LCD ma trn tch cc bc im nh

im nh im () transistor

bc im ()

Thi gian p ng ca LCD ma trn tch cc rt nhanh - xp x 16ms v cn nhanh hn. Thi gian p ng nhanh nh th s cho hiu sut tuyt vi i vi ng dng ha hoc hot nh. Mn nh ma trn tch cc cng cho gc nhn thoi mi khi xem 90 hoc cao hn. Ngoi ra, cc tn hiu li cao hn c th c dng vo vic to nh c tng phn cao v sng hn nhiu. Cc bt li ca LCD ma trn tch cc l gi cn cao bi chi ph xy dng xng TFT cao v cng ngh t dng vo vic ch to transistor nh xu (FET) ln trn bn knh. Gn nh mi LCD mu hin i - mn hnh my xch tay v my bn u s dng LCD ma trn tch cc (TFT). Kch thc mn nh Khi bn mua mt mn hnh CRT 17, th thng l 16,1 hoc hn vng xem mt cht, ty hng v nh sn xut CRT ring bit. S khc bit gia kch thc mn hnh v vng xem l bi khung cng knh v to ca CRT. Khng nh mn hnh CRT, mn hnh LCD c tip th bng kch thc mn nh thc t. iu c ngha nu bn mua mt mn hnh LCD, bn thc s c vng xem y 17, hoc rt gn bng vi 17. y l php o ca vng hin th c trn mn nh tnh t gc thp hn ti gc i din cao hn ca mn hnh. Di y l ch dn gn ng cho kch thc mn nh: 17 CRT = 15 TFT 19 CRT = 17 - 18,4 TFT 21 CRT = 19 - 20 TFT R rng iu ny khng phi lc no cng chnh xc, nhng n l ch dn gn ng cho kch thc. V d mt CRT 21 c th cho vng xem c ch hn 20. Ngy nay, mn hnh LCD 15 v 17 s t thy trn th trng bi cc nh sn xut tp trung vo m-en 19 v cao hn v h cng ang chuyn sang sn xut mn hnh dng mn nh rng.


ng cho (kch thc mn nh) mn hnh LCD mn nh rng Thi gian p ng l g? Thi gian p ng l c im k thut m c nhiu ngi, c bit l game th, quan tm hng u. N chuyn i khong thi gian phi mt mt (im nh) tinh th lng t trng thi hot ng (mu en) sang khng hot ng (mu trng) v li hot ng (mu en). Trong thut ng chuyn ngnh, n ni ti tc cc im nh v chng c th thay i t mu ny sang mu khc nhanh th no, v do nh c th c ko li nhanh th . S chuyn i ny c th thay i cnh nhanh cng tt. iu ny gip gim bt hiu ng bng ma/m trong game v phim m c th nhn thy nu thi gian p ng qu chm. Thi gian p ng tnh bng mi-li giy (ms). Con s cng nh c ngha thi gian chuyn i cng nhanh (v d 16ms nhanh hn 25ms). Nu bn gh mt i l my tnh bt k v nhn bng gi t h bn s thy c ch nh (ms) c in k gi ca mn hnh LCD. iu ny cho bit l mn hnh LCD c th th chy vi mi-li giy no. Ni chung mi-li giy (thi gian p ng) cng thp th gi ca mn hnh LCD cng cao.


phn gii t nhin Cu trc vt l ca mt s loi mn hnh, bao gm mn hnh LCD, TV LCD v bng plasma, cho nh ngha c bao nhiu im nh hin th c cng mt lc. Mn hnh cho nh sc nt nht khi c dng phn gii t nhin ca n. V mt vt l y l s im nh ngang v dc to ra ma trn mn hnh LCD. Vic thit lp mn hnh my tnh phn gii thp hn phn gii t nhin hoc s lm vng nhn thy c ca mn nh b ct gim hoc mn hnh s phi thc hin php ngoi suy. Php ngoi suy ny c gng pha trn nhiu im nh vi nhau cho nh tng t vi nhng g bn thy nhng n c th gy ra nh m nu mn hnh phi hin th phn gii thp hn phn gii t nhin. Di y l mt s phn gii thng thng mn hnh LCD: 14 -15: 1024 x 768 (XGA, cng l EGA, vit tt ca Extended Graphics Array$) 17 - 19: 1280 x 1024 (SXGA, Super XGA) 20+: 1600 x 1200 (UXGA, Ultra XGA) 19 (mn nh rng): 1440 x 900 (WXGA+, Wide XGA+) 20 (mn nh rng): 1680 x 1050 (WSXGA+, Wide Super XGA+) 24 (mn nh rng): 1920 x 1200 (WUXGA, Wide Ultra XGA) 30 (mn nh rng): 2560 x 1600 H s tng phn H s tng phn l cng c tip th quan trng theo cc nh sn xut v khng d dng ngi tiu dng nm c. H s tng phn lin quan ti s khc bit so snh ca hin th gia nguyn l mu trng sng nht vi nguyn l mu en ti nht. Nh mt quy c, h s tng phn cng cao cng tt. H s tng phn cao hn s cho mu tht hn t b bay mu hn. Chun xut cho m-en i cui thp hn thng l 700:1. Nhiu chuyn gia khuyn dng h s tng phn 1000:1 hoc hn. D g cng thn trng nhng li pht ngn trong kinh doanh, bi i khi chng c th c phng i. Mt s cng ngh khoe khoang kh nng kim sot tng phn linh hot v cung cp h s tng phn 3000:1 v cao hn! sng sng l thc o mu trng sng nht mn hnh LCD c th hin th c. Cc mn hnh LCD in hnh li qu sng yn tm s dng, v hin th mn nh (On Screen Display - OSD) dng iu chnh sng. sng cao hn mi tt bi n cho h s tng phn tt hn v c th c ch cho nhng cnh ti trong game/phim m ngi ta kh phn bit gia cc sc thi ca mu xm.

Chun hin th video ca IBM c d nh thay th cho chun c ca n l chun 8514 /A, v mang phn gii 1024 x 768 n cho cc mn hnh video tng thch IBM PC. Mt board XGA c trang b cng vi b nh ln (1 M) s c th hin th c 65.536 mu ch phn gii thp (640 x 480), v 256 mu ch phn gii cao (1024 x 768). tng thch li vi cc phn mm son tho theo cc chun c, cc board XGA cng ph hp vi chun VGA. Chun XGA ny ang gp s cnh tranh quyt lit ca cc nh sn xut cc b iu hp VGA pht trin (Super VGA phn gii cao). /* t in tin hc LC VIT 2002*/

$


Gc nhn Mt mn hnh CRT c th c nhn t hu ht mi gc , nhng vi mt LCD iu ny lun l vn . Gc nhn l mt xem xt c bit quan trng nu bn d nh cho nhiu ngi xem mn hnh LCD thi im bt k. Khi bn dng mt LCD, tm nhn ca bn thay i khi bn di chuyn gc khc nhau v khong cch t mn hnh. mt s gc l, bn c th nhn ra nh b m i (bay mu), v nhn nh th n s bin mt khi mt. L do l bi LCD sinh nh nh mt mng m khi dng in chy qua im nh, n bt sc thi ca mu. Vn vi mng LCD l mu ny c th ch c m t chnh xc khi nhn thng vo. Mn hnh LCD ni chung c nh gi da trn gc nhn r ca chng c chiu ngang v dc m da vo gc bn c th tch t tm im cht trc khi nh bt u bay mu. Gc nhn 180 trn l thuyt c ngha l n hon ton nhn r c t gc bt k trc mn nh. Nhiu ngh mt gc nhn ti thiu l 140 ngang v 120 dc. Gc nhn cng rng cng tt. Thng thng mc tng phn cao th gc nhn cng rng hn. Kt ni s v tng t Mn hnh LCD l thit b s v do phi chuyn i tn hiu tng t (Video Graphics Array$ - VGA) trc khi chng c th c hin th. Mt card ha vi giao din video s (Digital Visual Interface - DVI) c th gi tn hiu dng s thng ti mn hnh m khng bt buc chuyn i. Nhiu mn hnh LCD i km vi cng vo tng t (c mt u ni hnh ch D m c 15 chn sp lm ba hng, i khi gi l D-Sub), mt s i km c hai, v ch s t i km ch mt cng vo s. y l mt giao din s m c h tr cho php nh d nhn hn v sng hn so vi u ni chun VGA. Tuy nhin, v im ny, nhiu mn hnh LCD lm rt tt cng vic chuyn i tn hiu m kt ni s khng cn quan trng nh n tng.

Cng vo s (DVI)

Cng vo tng t (D-Sub)

Mt tiu chun hin th ha mu nh x bit, c IBM gii thiu vo nm 1987 cng vi lot my tnh PS/ 2 ca h. B iu hp VGA v mn hnh loi tng t c kh nng hin th 256 mu bin i lin tc cng mt lc, vi phn gii 640 pixel chiu ngang v 480 pixel chiu dc. Mch VGA tng thch li vi tt c cc chun hin th trc, bao gm CGA, MDA v EGA cao hn EGA khng nhng ch v phn gii cao, m cn v cng ngh VGA lun gi vng t l co dn ca cc hnh ha trn mn hnh. Chun VGA cng dng cng ngh tn hiu li vo dng tng t to ra mt s lng khng hn ch cc mu sc bin i theo mt di lin tc; cn EGA dng cng ngh mn hnh s nn b gii hn v s lng cc mc cng mu. Chun VGA ca IBM c cc ca hng thuc nhm ba nng ln cao hn, h a ra cc b iu hp VGA c kh nng hin th thm hai ch ha b sung. l ch Super VGA nng cao c phn gii 1024 x 786. Cc ch ny u c 256 mu c hin th ng thi. /*t in tin hc LC VIT 2002*/

$


Ch ng/nm Mt s mn hnh LCD xoay c sao cho l di hn c th i ngang (ch nm) hoc i dc (ch ng). Chc nng ny c th rt c ch cho k thut ch bn in t (trong ngh xut bn). Lt web, v xem bng biu ln, nhng ch c tr thm tin nu bn khng phi dng n n.

Ch ng Tui th mn hnh LCD

Ch nm

Tui th, in hnh l thi gian (s gi xem) cho backlight thuc loi trung bnh m i 50% sng nguyn thy ca n. Ni chung, mn hnh LCD dng c lu hn CRT. Tui th LCD thng l 50.000 gi s dng so vi 15.000 ti 25.000 i vi CRT. Tui th mn hnh cng lu th cng c li. ng dng LCD Bng LCD c dng trong cc ng dng khc nhau t thit b in t xch tay nh cho ti my nh v c nh ln. Cc ng dng nh thit b hin th dnh cho ng h s, my tnh b ti, mn hnh LCD v TV LCD, laptop v notebook, my chi game arcade, h thng ch ng cho xe hi, my mc cng nghip, phim v my quay s.


Tng quan cc mch mn hnh LCDHu ht mn hnh LCD c th hng su mch ch yu. Mi mch c chc nng ring ca n v trang ny ti s ch gii thch ngn gn tng quan mn hnh LCD v vic gii thch cn k hn chc nng tng mch s c gii thch r trong nhng chng sau. Mch cp ngun Nh tn gi ca n, vai tr ca cp ngun l cp in cho cc mch cn li trong mn hnh LCD. Thng thng in p ng ra l 12V v 5V v mc 5V li c h xung cn 3,3V v 2,5V nh IC n p. Tuy nhin mt s thit k mn hnh LCD, in p ng ra c th khc gi tr ti cp trn. Bn phi kim tra n bng ng h s vn nng. Mch cao p Cp in p cao v dng in cn c cho backlight. Cao p pht t 600 cho ti trn 1000VAC t mt, hai hoc thm ch bn bin th cao p ty vo c bao nhiu backlight c dng.

bo iu khin LCD

bo cao p

bo ngun

mainboard

bo bng iu khin

Bn trong mn hnh LCD


Backlight Pht ra ngun nh sng thch hp khng i. nh sng pht ra t backlight c tp trung vo LCD.

backlight mn hnh LCD

Mainboard/bo AD i tn hiu tng t RGB thnh tn hiu s v chuyn n ti bo iu khin LCD. Bo iu khin LCD Nhn thng tin hin th b sung t mainboard v iu khin cc transistor trong bng LCD. Bng LCD Kim sot nh sng ton din s dng vt cht tinh th lng.

bng LCD


S khi mn hnh LCDbacklighttin khuch i (Preamp), chuyn i tng t-s (ADC), vng kha pha (PLL), hin th mn nh (OSD), t chnh (Auto ADJ), tn hiu vi sai in p thp (LVDS), mch m gp (Scaler)thch anh

IC iu khin nh gi

mn nh LCD

backlightmch khuch i m thanh

EEPROM DDC 24LC21

loa

mch iu khin hi tip

IC EEPROM 24LC16 vi iu khin iu khin sng mch Buck Royer hay mch li trc tipmch khi ng

t chn lu

thch anh

bin th cao p

nt bm bng iu khin

LED

S khi ca mt mn hnh LCD hin i


Thng hiu bo cp ngunlc nhiu in t

Rush Prevention

chnh lu

bin th cp ngun ch ngt/m (bin th SMPS)

diode chnh lu v lc

n p

in tr mi 5V ti mainboard

mch ngt/m IC v mosfet iu khin iu bin rng xung

mch iu khin hi tip

S khi cp ngun mn hnh LCD thng thng

Cp ngun ch ngt/m dng cho cp in mn hnh LCD c th l kiu ngoi hoc trong. Chc nng ca cp ngun l i dng 230VAC chnh thnh in p ng ra DC cp cho cc bo cn thit trong mn hnh LCD.

cu chnh lu

t lc

bin th SMPS

diode Schottky

t lc ng ra

cu ch

IC cng sut

b ghp quang

bo cp ngun trong ca mn hnh LCD


Cp ngun kiu trong Ngun 230VAC vo cp ngun v ti chn xoay chiu cu chnh lu (thng l chn th hai v th ba). Dng AC sau c i thnh in p ng ra DC (khong 300VDC - khong 155VDC M) ni m t lc ln lc ht nhiu nh th m cp ngun s c hng s in p DC p. Dng DC in p cao ny sau c a ti transistor FET ngun ngt/m. Mch transistor FET ngt/m ny ngt m vi tc cc nhanh nh mt mch iu khin (IC cng sut) m pht ra cc xung sng vung c tn s rt cao.linh kin ngun my Dell E152Fpb

IC n p mch r chnh xc iu chnh c - TL431

b ghp quang

in tr cm bin dng in

FET 2N7000

FET ngun

MCR 100-6 SCRIC WPM UC3842B

FET ngun v IC cng sut (UC3842B) ring bit Mch transistor FETngt/m ngt m in p cao DC nhn c cng tn s cao v cho ng ra l cc xung sng vung. Cc xung sng vung ny sau c a ti cun s bin th ngun ch ngt/m. Cc xung ny cm sinh in cun s bin th s sinh ra in p ti cun th. in p ny cun th sau c nn v lc cho ng ra cn thit. Thng thng cp ngun c ng ra 12V v 5V vi 12V ng thi vo IC cao p v IC khuch i cng sut m thanh. 5V s qua mt hoc hai IC n p in ly 3,3V v 2,5V cp cho IC scalar, vi iu khin, EEPROM v bo iu khin LCD.


hai ng ra cung cp in p cho cc mch khc

t lc

bin th SMPSIC cng sut

cu ch bo cp ngun mn hnh LCD Samsung

Transistor FET ngun c tch hp sn vo trong IC cng sut Lu l thit k cp ngun mn hnh LCD nhiu kiu gn y nht c transistor FET ngun ngt/m c tch hp sn vo trong IC cng sut do bn s khng tm ra FET ngun trong bo cp ngun. Cp ngun kiu ngoi

LED

ng vo AC

jack cm ng ra

adapter ngun mn hnh LCD


adapter ngun mn hnh LCD loi 12VDC 3A

Thng s adapter ngun mn hnh LCD Thng thng ng ra t cp ngun ngoi l 12V, 14V hoc 18V vi cng gii hn t 2A ti 4A. Nu bn mun thay mi cho adapter ngun, chc chn rng bn hiu c thng s l n phi ging hoc cao hn adapter c v cng ch khng phi in p. in p th phi nh nhau! Mt khi in p vo mn hnh LCD, in p s qua mt vi IC n p thnh 5V, 3,3V v 2,5V cp cho bo iu khin LCD.

jack cm ng vo cp ngun ngoi

mainboard mn hnh LCD

Gn jack cm ng vo ca cp ngun ngoi cho mainboard mn hnh LCDPDF created with pdfFactory Pro trial version www.pdffactory.com

Kim tra cp ngun ngoi Nu bn mun kim tra liu cp ngun ngoi tt hay khng, bn cn gn n vo ngun AC v quan st n LED. Nu n khng sng r rng l adapter xu nhng u tin bn phi chc chn l in p dng xoay chiu vo adapter. D l n LED sng bn vn cn o li bng ng h vn nng xem in p ng ra c ng vi thng s khng. i khi mt t lc xu trong mch adapter ngun c th gy st vi Vn v bn c th ngh rng in p ng ra l tt bi n LED sng.

mi adapter ngun u c sai s m khng cn ti, 12VDC c th ln thnh trn 12V! (c l 12,32VDC nh hnh)

km tra in p ng ra adapter ngun mn hnh LCD

Cch ng kim tra in p adapter Ti gp adapter ngun c kim tra tt (in p ng ra ng vi thng s) bng ng h vn nng nhng tht bi khi cm vo mn hnh LCD. Adapter ngun b li lm mn hnh LCD b nhp ngun hoc thm ch t tt sau vi giy. Cu hi t ra l lm sao bit adapter ngun b li hay mn hnh monitor c vn ? Rt n gin phn on - dng bng n sau xe hi 24V v mc vo jack cm ng ra adapter ngun. Bng n phi sng lin khng st cht in p no khi kim vi ng h s. Nu c st in p mt cht hoc LED nhp nhy mt ln lc mc bng n vo, chng ta c th cho rng adapter ngun c vn . Hu ht l bi gi tr in tr trong cao t lc ng ra ni n khng th duy tr in p ng ra khi c ti (bng n) mc vo. Bn c hai chn la - mua adapter ngun mi hoc hi khch hng ca bn c cho php tho adapter ngun ra khng. Hu ht adapter ngun c hn kn v bn cn mt ci ca nh xn. Cng khch hng ca bn bit rng mt khi saPDF created with pdfFactory Pro trial version www.pdffactory.com

adapter ngun, c th li mt vi vt cong nh. Nu khch hng ca bn tn thnh yu cu th c th tho ngay v thc hin vic sa cha. Kim mi t in u tin trc khi bn ti linh kin khc tr khi adapter ngun b hng bi st nh, v.v. Mt khi xong vic sa cha, hy bt kn n bng nha dnh (bn c th d dng mua n ca tim phn cng bt k). Nu adapter ngun c nhiu linh kin b chy trong th hy tnh chuyn mua mi bi khng sa c!

Dng bng n xe hi kim tra in adapter ngun


Thng hiu mainboard/bo ADDDC EEPROM

vi iu khin

IC n pIC scalar

IC LVDSEEPROM

thch anh

maninboard mn hnh LCD Samsung

Mt s k thut vin gi n l mainboard, s khc l bo AD v s khc na gi n l bo logic hoc bo scalar. Mc ch ca bo ny l i tn hiu tng t RGB thnh tn hiu s v gi n ti mch iu khin v li LCD v sau cng l ra mn nh LCD. Bo ny gm IC scalar, vi iu khin, EEPROM, thch anh, IC n p v linh kin dn chung quanh khc. Bo ny thng c cp 2,5V, 3,3V v 5V. Trong mt s thit k nh Samsung, mainboard c nhiu vn nh mt hnh, mt hnh chp chn, OSD li ch ti u, v.v. trong khi vi mt s thit k nh Dell, th rt mnh. Sau y l chc nng tng IC trong mainboard: IC scalar - n gm tin khuch i (Pre-Amp), chuyn i tng t sang s (Analogue to Digital Converter - ADC), vng kha pha (Phase Locked Loop - PLL), hin th mn nh (On Screen Display - OSD), b pht tn hiu vi sai in p thp (Low Voltage Differential Signalling - LVDS) knh i v IC chia t l trong n. IC chia t l bn trong IC scalar s i tn hiu ng vo tng t ca mu , xanh l v xanh dng thnh tn hiu s c 8 hoc 16 bit (ty vi iu khin c dng) ca mu , xanh l v xanh dng m IC iu khin trong bng LCD nhn bit c. Chc nng t chnh cung cp tn s t ng, pha, v tr H/V v cn bng trng iu chnh iu kin mn nh bt k. Vi mn hnh LCD xa hn th ADC, OSD v b pht LVDS khng c tch hp vo trong IC scalar. Vi iu khin (MicroController Unit - MCU) - vi iu khin l mt my tnh con ng trong mt IC v c lp trnh cho mt nhm cc cng vic ring bit. Vi iu khin gm CPU, SRAM, DAC, chuyn i tng t/s (A/D Converter) v chng trnh bn trong 64KB gi l Flash ROM. N ci thin hiu sut ghi/xa v kh nng ghi nh d liu cho Flash (cho php ngi dng nh ngha chng trnh c yu thch hn ca ring h), lp trnh nhanh hn v s ln xa ca b nh Flash v Flash c th dng sao EEPROM.PDF created with pdfFactory Pro trial version www.pdffactory.com

thch anh

IC EEPROM 24C16

s vi iu khin

S mch vi iu khin ca mn hnh LCD

thch anh 27MHIC EEPROM 24C02

IC scalar

EEPROM 24C16 vi iu khin mainboard mn hnh LCD

IC EEPROM - EEPROM l vit tt ca b nh ch c c lp trnh v xa bng in (Electrical Erasable Programmable Read Only Memory) v cng c gi l E2PROM. Nh tn gi, EEPROM c th va c xa va c lp trnh nh xung in. Bi n c th va c ghi bng in va c xa bng in,PDF created with pdfFactory Pro trial version www.pdffactory.com

EEPROM c th c lp trnh v xa nhanh chng trong mch cho vic lp trnh li m khng cn loi b chng ra khi bo mch. EEPROM cng c gi l b nh khng i bi khi ngt in th d liu gi trong EEPROM s cn nguyn vn khng b xa. EEPROM mi khng c d liu trong n v phi lp trnh bng my lp trnh trc khi c th dng c. Thng tin trong b nh loi ny c th c gi tip tc trong nhiu nm m khng cn cp ngun u n. Chc nng ca EEPROM l g? EEPROM dng gi thng tin lp trnh c ca ngi dng. EEPROM trong mn hnh LCD thc hin hai chc nng: * Khi mt mn hnh LCD c bt n s copy mi d liu hoc thng tin t EEPROM ti vi iu khin. V d, EEPROM s cho vi iu khin bit tn s m mn hnh sp vn hnh. * EEPROM dng gi cc thit lp hin thi ca mn hnh LCD. Cc thit lp ca mn hnh s khng b xa ngay c khi tt mn hnh. Khi c thay i bt k trong cc thit lp mn hnh th vi iu khin s cp nht thit lp trong EEPROM. Khi mn hnh bt li, cc thit lp gi dng thit lp cho vic vn hnh mn hnh. Cc triu chng khi d liu EEPROM mn hnh LCD b sai hoc hng? * Mt hnh. * C ln sng ngang hoc dc. * Khng th lu (gi) thit lp hin thi. * Cc chc nng iu khin no nh iu khin m thanh, sng v tng phn khng chy. * Hin th mn nh (On Screen Display - OSD) khng chy hoc s hin th sai.

gn vo cng ni tip my tnh

my lp trnh EEPROM


My lp trnh hay my copy EEPROM l g? EEPROM t khi h, chng ch mt hoc b nh (d liu) ca chng b sai. Mt khi c lp trnh li chng tt nh mi. Nh cp t trc, EEPROM mi cha c g v cn thng tin hoc d liu np cho n chy. Cng vic sao d liu vo trong EEPROM c thc hin bng my lp trnh hay my copy. Sau y l vi EEPROM ph bin cng nhm tm thy trong mn hnh LCD. 24C02 hoc 24C21 - EEPROM ny gm (gi) d liu DDC$ (Display Data Channel - knh d liu hin th) v giao tip my tnh thng qua cp tn hiu. Cc chun DDC ny h tr tnh nng Plug and Play. Chun DDC n gin ha vic ci t mn hnh cho ngi dng. Cng ngh DDC cung cp c ch cho chng trnh c s (firmware) phn h video v h iu hnh t ng xc nh cc kh nng ca mn hnh gn lin, v sau cu hnh cc thng s vn hnh ph hp ca mn hnh. 24C04, 24C08 hoc 24C16 - EEPROM ny gi cc thit lp hin thi ca mn hnh LCD. Nu c thay i trong vic thit lp mn hnh (v d thit lp tng phn ln ht c), vi iu khin s cp nht cc thit lp trong IC EEPROM. Do khi mn hnh LCD bt li, thit lp gi ( tng phn ti a) dng thit lp cho vic vn hnh mn hnh. Thch anh - Chc nng l gi tn s xung clock khi b lch. Nu tn hiu t xung clock ny ngng cp tn s, hoc b yu, hoc cc xung bt u bin thin hoc thay i, mn hnh LCD c th l ra cc vn chp chn hoc c th tt hn. Hy chc chn c sng hnh sin khi kim tra bng my hin sng. IC n p - cp dng 2,5V, 3,3V v 5V khng i ti mi IC trong mainboard v bo iu khin. Dng thp hoc mt mt trong cc mc in p c th gy mt hnh v n LED cng khng sng.

DDC EEPROM l chp nh giao tip vi my tnh gip my tnh nhn bit m-en trong qu trnh ci t v ti trnh iu khin mn hnh.

$


Thng hiu bo cao p

bo cao p

bo ngun

Vi thit k mn hnh LCD mi hn, bo cao p nm cng vi bo ngun nh hnh trn. Mn hinh LCD xa hn c bo cao p ring bit vi bo ngun nh hnh di

bo cp ngun

backlight trn

IC 74HC02 TTL thit k mn hnh LCD i c hot ng nh IC cao p

cu ch

backlight di

t chn lu

thit k mn hnh LCD xa hn c bo cao p ring bit vi bo cp ngun

bin th cao p


C bn kiu thit k cao p c dng trong mn hnh LCD 1. Cao p Buck Royer$ 2. Cao p y ko (li trc tip) 3. Cao p na cu (li trc tip) 4. Cao p ton cu (li trc tip) S 2, 3 v 4 c gi l li trc tip nh b i s cn thit c cun cm (cun Buck) v cc t in cng hng thy bng my hin sng Royer thng. Ni cch khc, kin trc li trc tip gim bt tng s linh kin, chi ph sn xut thp hn v quan trng hn ht l ci thin thit k bin th m ti u ha hiu sut. 1. Cao p Buck Royer

cng tt on/off

mch dao ng

bin th cao p

backlight CCFT

on/off t mch khi ng

IC cao p chnh sng

mch hi tip

s khi ca mch cao p

S khi ca cao p Buck Royer

$

Buck v Roger l tn ca hai nh khoa hc Jeffrey P. Royer v John R. Buck


IC cao p

vng cp ngun

cun Buck

FET knh P bin th cao p

diode Buck transistor y ko t chn lu

t xoay

mch cao pmch backlight trn hai backlight mch backlight di

`

FET knh P kiu Buck

bin th cao p cun Buck t xoay t chn lu

n

diode Buck

IC cao p transistor y ko mch hi tip

Lc ca mch Buck Royer


FET knh P kiu Buck

t xoay cun Buck

t chn lu

diode Buck bin th cao p transistor y ko mch hi tip

IC cao p

mch cao p

S ca cao p Buck Royer trong mn hnh LCD li backlight (n CCFT) c nhng trong m-un bng, i hi mch cao p phi i 12VDC thnh in p ng ra AC ln ti c trm hoc thm ch trn mt ngn. Cao p to ra t h thng in i xng li cc m-un n ring bit. Tng ng vo (mch cao p kiu Buck) gm IC cao p, FET knh P kiu Buck, cun Buck v diode Buck. Mch cao p kiu Buck i in p DC thnh in p DC thp hn. Tng kia gm cc t xoay, bin th cao p, v cp transistor y ko tng ng ra AC ln c trm Vn. T chn lu iu khin bin dng in nh tr khng m n bng cch gi mt in p tng ng qua tr khng dng ca n. Mch hi tip l cho mc ch bo v v s ngt IC cao p phng trng hp nu in p cao c cp bi bin th cao p vt qu gi tr bnh thng v cng nh n c th pht hin cc backlight hng hoc rung. IC cao p cng dng iu khin sng cc n CCFT. Tn s dng AC ca bin th cao p thng t 30 ti 70KHz. Tn s cng cao, nh sng cng mnh. Lu : Mt s thit k mn hnh LCD c FET knh P kiu Buck c tch hp vo trong mt IC do kim tra chng bn c th dng phng php so snh vi mt FET cn tt khc (so snh gi tr Ohm gia cc chn) hoc dng thit b Peak Atlas Component Analyser. IC c th l hai hng chn hoc loi dn.


IC hai hng chn

Hai IC trn c th c mt hoc hai mosfet trong.

FET knh P kiu Buck

FET knh P c tch hp vo trong IC


D dng kim tra FET c tch hp vo trong IC vi Peak Atlas Component Analyser FET knh P kiu Buck ph bin l FU9024N, J598, v.v. IC FET dn ph bin l 4431, BE3V1J, v.v. M s trn thn transistor y ko ph bin l C5706, C5707, v.v. 2. Cao p y ko (li trc tip)

t chn lu nhnh gia cp VCC n

bin th cao p

IC cao p hai FET knh N v P c th c tch hp vo trong IC mch hi tip

Cao p y ko trn cho thy khi Q1 m, dng in chy qua na trn ca s cp T1 v sinh t trng trong T1. T trng ny cm in qua th cp T1. Khi Q1 ngt, t trng trong T1 yu v sau mt thi gian (ty chu ky cng sut ca tn hiu li dao ng), Q2 dn, dng in chy qua na di ca s cp T1 v sinh t trng trong T1. Gi th hng ca lung t tnh ngc vi lung sinh lc Q1PDF created with pdfFactory Pro trial version www.pdffactory.com

dn. T trng sinh ra cm in qua thc cp T1. Sau mt thi gian, Q1 dn v chu k lp li. S trn ch cho thy IC knh n li Q1 v Q2. Mt s IC cao p c th c hai knh li hai bin th cao p. Mi ng ra t bin th c th li nhiu hn mt n. Lu im ny! 3. Cao p na cu (li trc tip)

lc ca cao p na cucp VCC

t chn lu n

bin th cao p

IC cao p hai FET knh N v P c th c tch hp vo trong IC mch hi tip

Cao p na cu tng t cao p y ko, nhng khng i hi c s cp nhnh gia. C cu o ca t trng c c bng cch o chiu dng in cun s cp. Kiu cao p ny cng thy trong nhiu mn hnh LCD. Mch iu khin ca cao p na cu tng t vi cao p y ko. Thit k ny tn dng ti u li bin th v cun s cp (mt li ch khng phi hai li bn cao p kiu y ko). S trn ch cho thy IC knh n li Q1 v Q2. Mt s IC c th c hai knh iu khin hai bin th cao p. Mi ng ra t bin th c th li hn mt n. Lu thm im ny!


mn hnh LCD i c thit k FET knh P v N theo hnh dng IC

ni vi n t chn lu

FET knh P t IC 74HC02

T IC 74HC02 theo thit k ny th khng c mch hi tip

FET knh N

s khi ca cao p na cu thy trong mn hnh LCD i c

bin th T2 song song vi T1

S ca cao p na cu 4. Cao p ton cu (li trc tip)

bin th cao p

n IC cao p

FET i trong mt IC

mch hi tip

Cao p ton cu tng t cao p y ko, nhng khng i hi s cp nhnh gia. C cu o ca t trng c c bng cch o chiu dng in cun s cp. Kiu cao p ny thy trong nhiu mn hnh LCD i mi. Cc cp transistor cho nhau s thay phin dn, do dng in sinh ra o chiu trong s cp bin th. C th minh ha th ny - vi Q1 v Q4 dn, dng in sPDF created with pdfFactory Pro trial version www.pdffactory.com

chy v pha di s cp bin th v vi Q2 v Q3 dn, v dng in s chy v pha trn s cp bin th. Mch iu khin theo di in p ra v iu khin chu k cng sut ca dng sng li ti Q1, Q2, Q3 v Q4. Mch iu khin hot ng cng mt kiu i vi cao p y ko v cao p na cu, ngoi tr c ti bn transistor (FET) li ch khng phi hai. Trong mt s mn hnh LCD nh HP1703 s dng IC cao p OZ960, ng ra t IC cao p c th ra song song li thm bin th cao p khc nh hnh.

bin th cao p

bin th cao p hai IC ny li bin th di hai IC ny li bin th trn

IC cao p

mch cao p ton cu

Bo cao p ton cu

IC cao p

nhn t mt sau bo cao p: cch mt mch cao p ton cu mc vi nhau

bin th cao p IC mosfet cng sut knh N v P i

bin th cao p

Thit k cao p ton cu c bn IC (mi IC c hai FET (knh N v P) trong). Hai IC dng li hai bin th cao p.


IC S0-8 loi dn

G = cc cng, D = cc tho, S = cc ngun

IC mosfet cng sut knh N v P i Nh l IC mosfet cng sut knh N v P i c th l loi dn hoc hai hng chn. Cc li hay gp bo cao p 1. 2. 3. 4. 5. 6. 7. 8. Kh ch mi hn (rt hay gp cun Buck v bin th cao p). Chm hoc chy bin th cao p. Cc transistor y ko b chm hoc r r. Sai gi tr in dung t xoay. Chm FET knh P kiu Buck. Cu ch Pico cao p b t hoc tng tr s. t t chn lu lm sng thay i bt thng v t tt. Chy chn hoc lng chn u ni backlight.

ng ngc nhin l cc IC cao p rt mnh v t h. Vi IC cao p ph bin cng nhm l TL1451ACN, 0Z960, 0Z962, 0Z965, BIT3105, BIT3106, TL5001, v.v. o in p v dng sng trong bo cao p xem chng im o in p chun mn hnh LCD v im o dng sng chun mn hnh LCD


Thng hiu mch khi ngHu ht mn hnh LCD c mch khi ng iu khin in p t cp ngun ti chn cp ngun IC cao p. Tn hiu iu khin chnh ti t mainboard v in p l t 0 ti vi Vn (2 - 5V). Nu tn hiu l 0V, th IC cao p s khng nhn in p no t cp ngun v nu tn hiu l 2V (bt) th IC cao p s c bt v bin th cao p s hot ng v cc backlight s sng. Mch khi ng l im khi u tt phn on v sao mn hnh LCD c vn mt hnh, t tt v mt hnh chp chn.

ti mch khi ng

bo cao p

tn hiu on/off

t mainboard

nh du on/off trong bo cao p Nhn s di: cch mch khi ng ny lm vic. Khi mn hnh LCD c bt (gi s u ni VGA cm vo CPU h thng my tnh) mainboard u tin s gi i tn hiu bt (BL-ON) (khong 2 - 5V ty thit k mn hnh LCD) ti cc nn B ca Q751. Tn hiu on lm Q751 bt v dn theo Q752 bt. Do 12V chy t cc pht E v ra ti cc thu C v ti chn (cp) VCC ca TL1451ACN (IC cao p). F751 l cu ch Pico (mt s l cu ch dn) v tiu th mc 2A 125V.


t cp ngun

transistor mch khi ng

tn hiu t mainboard

ng vo in p cung cp

IC cao p

S mch khi ng trong mn hnh LCD Nu mainboard khng gi tn hiu on (bi c vn trong mainboard) ti cc nn B ca Q751, transistor Q752 s khng bt do khng c in p chy ti chn cp VCC ca IC cao p lm mt hnh mn hnh LCD.


transistor mch khi ng

in p i

chn cp VCC IC cao p

IC cao p

cu ch dn

tn hiu bt/tt t mainboard

Mch khi ng thng thng trong mn hnh LCD Cc thit k khc c th dng C945 v A733 thnh cp kt hp trong mch khi ng trong khi mt s thit k nh Samsung 153V dng A6J (transistor s PNP) v A8J (transistor s NPN) nh hnh di. C hai transistor u l transistor s v c cc in tr (4,7K + 4,7K) mc vo trong transistor. Ti nhn c nhiu email hi cch phn on mn hnh LCD triu chng c ngun nhng mt hnh. Tht ra rt d kim tra nu vn nm trong mainboard, mch khi ng hoc thm ch trong chnh IC cao p.

mass ngui

t que vo chn bt/tt ti u ni v que en vo mass ngui


t que ng h s vo chn on/off nh hnh v que en vo mass ngui bt k. Gi bt mn hnh LCD v c in p. Nu c in p (2 ti 5V) bn c th chc chn mainboard chy v gi tn hiu ng. Nu khng c in p cho bit mainboard ang c vn . Mn hnh LCD Samsung cc m-en 153V, 173V, 510N, 710N, 713N v 913N rt hay gp vn mt hnh (khng gi tn hiu on) v vn mt hnh chp chn v gy ra bi h hng trong vi iu khin.

chn 9 l chn VCC

in p i

in p cung cp

mch khi ng IC cao p dn tn hiu t mainboard

Mt mch khi ng khc mn hnh LCD Tip theo nu c tn hiu on th chc chn ti chn cp VCC ca IC cao p c khong 9 ti 12V. Nu c tn hiu ng vo ti cc nn B ca transistor mch khi ng v khng c tn hiu ng ra ti chn cp ngun IC cao p, nghi ng linh kin khu vc mch khi ng b h hoc thm ch cu ch Pico b li cng s ngn in p cung cp ti IC cao p. Khng c b qua chi tit IC cao p b chm c th ko in p cung cp xung mc rt thp nu khng t cu ch. Nu c th, trc tip thay IC cao p v kim tra mn hnh LCD ln na. i vi vn mt hnh chp chn tht ra bn c th nhn thy t ng h c in p tn hiu on/off ln v xung v y l du hiu r rng ca vi iu khin hng. Hy th thc hnh nhiu trn mn hnh LCD tt v bn s khng mt nhiu thi gian tm ra h hng l mainboard, mch khi ng hay khu vc mch cao p.


Thng hiu backlight (n)

backlight (n) trong mn hnh LCD

Bng LCD t n khng th pht sng. Do , mt h thng backlight cung cp nh sng t pha sau l bt buc phi c. H thng backlight gm mt thit b pht nh sng cho ra nh sng, mt bng dn a nh sng ti ton b b mt LCD khng thay i, v mt cp ngun iu khin thit b pht nh sng. Cc backlight c th c nhiu chiu di v hnh dng khc nhau.

bng LCD t n khng th pht sng. Do , mt h thng backlight cung cp nh sng t pha sau l bt buc phi c


dy backlight di khu vc cao p

mainboard

bo ngun dy backlight trn

Cc phn bn trong mn hnh LCD Ngy nay, thit b pht sng c dng ph bin l ng hunh quang m cc lnh (Cold Cathode Fluorescent Tube) hoc CCFT. CCFT gi l ng hunh quang m cc lnh bi d nguyn l ca ri l nh nhau so vi ng m cc nng c s dng bi cc n trong nh, n m cc lnh khng i hi nung s dy tc. Ngoi ra, cc in cc ti ui bng n gi mc nhit thp trong khi pht ra nh sng. CCFT cng rt bn (xp x 50.000 gi) m khng c suy gim nghim trng no. Cp ngun c bit, cao p, pht xp x 600 ti ngn AC l mc phi c li CCFT. Cao p ny l cp ngun nh lm CCFT ny chiu sng, v l mt trong cc phn c chc nng quan trng ca mt mn hnh LCD hon chnh. Hnh rung v Thng thng, hnh v hnh rung mn hnh LCD gy ra bi khim khuyt backlight (backlight trn hoc di). i vi cc mn hnh LCD khng c mch hi tip trong bo cao p, d backlight c vn th mn hnh LCD vn hot ng tip v khng bao gi t tt. iu ny hon ton khc so vi mn hnh LCD c mch hi tip trong bo cao p l thm ch mt ci rung nh mn hnh gy ra bi khim khuyt backlight, mn hnh LCD s t tt ngay.


bn phi ko n ra xem tnh trng ca n

ui b en

ui n b en c th lm mn hnh LCD rung v tt

Cho thy ui b en backlight mn hnh LCD

bin th cao p

t chn lu

bo cao p in hnh c mch hi tip

cc u ni backlight


t chn lu mch hi tip

bin th cao p

bo cao p nhn t mt sau

bin th cao p

dy backlight

t chn lu bo cao p khng c mch hi tip

t chn lu bin th cao p

u ni backlight bo cao p


t chn lu

bin th cao p

bo cao p khng c mch hi tip

Thay backlight

tho n t bng LCD

Cch ng ly backlight ra khi bng LCD thay backlight thnh cng bn phi ko nh backlight ra cng vi v ca n nh hnh trn. Mt s backlight c th tho d dng trong khi s khc th kh. i vi backlight c hn kn, bn phi cn thn khi g backlight. Mt ln ti v tnh git mnh TCP khi tho backlight v bng LCD khng dng c na bi mn hnh c mt sc en ln. TCP rt d t v bn nn lu ti n nhiu hn khi c tho ri bng LCD kim tra hoc thay backlight.


Tape Automatic Bonding (TAB)

bng LCD

Tape Carrier Package (TCP)

ch ny rt d gy

khi tho backlight chc chn rng bn khng git mnh TCP bi n rt d t

bo iu khin

Mt khi TCP gy khng c cch g sa Cu hi lin quan ti backlight 1. Lm sao bit backlight tt hay xu? Bng cch dng backlight tt t mn hnh LCD khc hoc backlight bn mua d phng. Nu u ni backlight thch hp, ch cn ni ri th. Nu mn hnh b hoc rung kh nng l backlight b li. Bn phi tho li backlight v xem ui c b en hay khng. 2. C th lp backlight 15 vo trong mn hnh LCD 17 khng? C, nhng hin th trn v di s khng c che kn ht (bi backlight 15 ngn hn backlight 17) v bn c th thy mt s ch ti hn ti cnh mn hnh. 3. C th thay backlight t mn hnh LCD cng kch thc nhng khc hng (gi s t mn hnh LCD 15 cho 15) khng? C, chc chn nhng bn phi kim tra li cng ca backlight t mn hnh LCD khc d n cng kch thc mn hnh. Nu thay ri m nhn ti hn so vi backlight ban u (gi s bn thay backlight trn) th ti ngh bn phi thay lun backlight di (d backlight di cn tt) c s cn bng cng nh sng. Bn c th gi li backlight di dng sau ny. 4. C th t mua backlight mn hnh LCD u? Bn c th xem cc website c trong thng tin gii thiu chng cui.


5. C nn mua backlight d phng khng? Ty ti tin ca bn; bn c th t mua d phng v x l s c. S khng phi ch nu bn tnh c gp mn hnh LCD c vn vi backlight. Backlight d phng c th gip bn phn on nhanh vn . Bn s bit ngay nu mn hnh LCD c vn nh t tt, rung, , m, v.v. gy ra bi backlight b li hoc bi khng thay backlight tt.

Th thut b mtCch gii quyt hnh rung m khng phi thay backlight Thng thng trong mn hnh LCD thit k i mi (c mch hi tip) khi mn hnh b rung (thm ch rung rt nh) mn hnh s t tt ngay. iu ny c th xy ra c bit vi mn hnh LCD s dng IC cao p loi 0Z960. Quan st k mn nh ch b rung u tin. Nu n bt u t trn ri lan xung di nghi ng backlight trn b hng. Nu n bt u t di v lan ln phn trn ca mn nh nghi ng backlight di. Tht ra bn c th nhn thy ch no bt u rung trc nhng cng c tnh trng, bn phi tp trung v lu trn mn nh d c mt thi gian. Mt khi bn xc nh ra backlight b h (gi s backlight trn) sau bn s thay bng backlight mi. Khng phi lc no cng ng, i khi i vi vn backlight rung ngn bn tht ra c th sa li mch hi tip mn hnh LCD tip tc chy m khng t tt.

backlight trn ca cao p backlight di ca cao p

Bo cao p Lm sao sa li mch hi tip? D t mch hi tip backlight di v tm in tr bt k xung mass ngui. Tho v thay bng mt chit p. Bt mn hnh v chnh ti khi n khng cn t tt na.


IC cao p phn mch hi tip

Khi bn mun sa li mch hi tip th tm in tr xung mass ngui

V d trng hp thc t

ti thay in tr 360 bng chit p 1K

Mn hnh LCD HP1702 b rung nh backlight trn. Ti d t mch hi tip v tm ra in tr (R120) xung mass ngui. Ti thay n bng chit p 1K v bt mn hnh. Sau ti chnh ti khi n khng cn t tt na. Ti tho chit p v o gi tr Ohm c 238. Sau ti thay in tr bng in tr 240 v mn hnh LCD chy tt m khng b rung na!


ni chn gia

tho in tr hi tip v thay bng chit p

D sao th nu mn hnh LCD rung rt xu v b th cch duy nht l thay backlight mi.

phng!Khng c ng vo n b bng tay khng bi n c thy ngn. Thy ngn c bit l rt c hi cho c th ngi!


Thng hiu bng LCDkhung c mn nh LCD

bng LCD

Bng LCD gm khung c, bo iu khin, TCP, TAB, cc IC li LCD, backlight (n), knh phn cc, mng khuch tn, knh dn nh sng v mng phn quang. Mc ch ca bng LCD l ton iu khin nh sng s dng vt cht tinh th lng.

v kim loi sau lng

phn quang

backlight trong ny knh dn nh sng

mng khuch tn

Khung c gi bng LCD v gip gim nhiu in t (Electronic Magnetic Interference EMI)


Bo iu khin Mc ch ca bo iu khin l chp nhn thng tin hin th thm vo t mainboard v sau li cc transistor li ct v cc transistor li hng m im nh trong bng LCD s sng hoc tt. Cc transistor trong bng LCD c iu khin bi cc tn hiu iu khin s sinh bi IC li LCD v c iu khin bi IC iu khin.

IC li LCD

IC li LCD

bo iu khin

IC iu khin LCD

bng LCD

bo iu khin


u ni ti mainboard IC iu khin LCD

cu ch dn

bo iu khin LCD


Tape Carrier Package (TCP) TCP h tr c v c v in cho cht bn dn (cc IC) li LCD gia bng LCD v m-un li cho ng dng mn hnh bng phng.

mn nh LCD


IC li LCD

bo iu khin

Tape Automatic Bonding (TAB) TAB l cng ngh ni lin gia cht nn (trong mn nh LCD) vi IC (trong TCP); s dng gi lm sn vi ch c m ng thay v dy in n. Backlight Pht ngun nh sng c, u. nh sng pht ra t backlight u tp trung vo LCD. Knh phn cc L mng mng cho php nh sng qua ch theo mt hng. Gia cc mng knh phn cc cha b lc mu, knh lc mu, tinh th lng v knh TFT (transistor mng mng).


Mng khuch tn c dng trong gia cng bng LCD m bo ri hin th c u, cng nh cng nhiu nh sng ti ngi xem cng tt.

mng khuch tn v kim loi sau lng knh phn cc

cc bo iu khin

phn quang

knh dn nh sng

Knh dn nh sng Cc knh dn nh sng phn b u nh sng t cc backlight, c lp pha trn v pha di mn hnh, trn khp ton b mn nh. Mng phn quang Nhn nh sng t cc backlight gi li nh sng ti knh dn nh sng.

Thay bng LCDNu bng LCD c vn nh nt, cu vng, hng bo iu khin, mt hoc vi ln sng dc, ng en ngang ln, gy TCP, v.v. cch gii quyt duy nht l thay bng bng LCD cng loi. Bn khng th thay bng bng LCD khc loi bi chi tit k thut khc nhau v cc u ni, cc dng tn hiu, in p, v.v. l l do v sao tht sng sut khi mua li cc mn hnh LCD m khng th sa c (hng cp ngun hoc cao p nhng bng LCD cn tt) t khch hng. Hu ht khch hng mun bn nu bn tr gi cao mt cht.


Ch bo tr hng mn hnh LCDHu ht cc mn hnh LCD u c ch bo tr hng. Vy chnh xc th ch bo tr hng l g? Khi cc nh sn xut mn hnh thit k mn hnh LCD, h thit k hai kiu iu khin tc l mt cho ngui dng iu khin thit lp hin th (nt chnh pha trc) v mt iu khin khc d phng cho nh sn xut thc hin cc thit lp bn trong. Cc thit lp bn trong mn hnh LCD l g? Mt s mn hnh LCD c nhiu thit lp bn trong cn s khc ch c vi chc nng thng thng. Cn bng mu RGB, v tr, kch thc, ngn ng, thng tin (s gi s dng) ca backlight v bng LCD, v.v. Hu qu ca vic chnh sai cc thit lp trong ch bo tr hng l g? Nu bn nhm ln chnh sai thit lp trong ch bo tr hng bn c th lm h mn hnh (do mt d liu, v.v.). L k thut vin sa cha chng ta phi chu trch nhim nu cc thit lp bn trong mt tc dng! Do nn ghi li gi tr ban u trc khi chnh thit lp trong mn hnh LCD bt k. Nu bn khng chc v cc thit lp chc nng th ng chnh. Li ch ca vic dng ch bo tr hng mn hnh LCD l g? a. Bn c th kim tra thi gian (s gi) mn hnh LCD dng trong bao lu nh backlight v bng LCD. iu ny chc chn c li cho nhng ai mun mua mn hnh LCD c hoc tn trang nu h bit cch v ch bo tr hng. Thi gian (s gi) mn hnh LCD dng cng t cng tt. b. Bn cng c th kim tra ngy thng sn xut mn hnh LCD. Bn s bit iu ny khi mua mn hnh LCD mi, nu n l m-en mi. Khng phi mi ch bo tr hng u hin th ngy thng sn xut. c. Bn c th tm ra m-en/s ph kin ca bng LCD nh ch bo tr hng. iu ny gip tit kim thi gian bi bn c th trc tip t mua bng LCD mi. Mt ln na, khng phi mi ch bo tr hng u hin th thng tin ny. d. Nu bn lp trnh li IC EEPROM bng my lp trnh v thy vn cha hi lng vi cht lng nh (khng cn xng v mu, v tr v kch thc) bn c th dng ch bo tr hng chnh cc thit lp ti khi hi lng vi mn hnh. Ch bo tr hng c gii quyt c vn mt hnh, t tt v hnh lc khng? Khng, cc vn ni trn l bi li mch in (trong ngun, mainboard, cao p v bng LCD) v khng th gii quyt bng ch bo tr hng! Lm sao v ch bo tr hng mn hnh LCD? Cc nh sn xut khc nhau c cch v ch bo tr hng khc nhau. Thng tin ng nhp ch dng c i vi k thut vin bo tr v k s ca cc nh sn xut v c cc trung tm bo tr y quyn nhng i khi bn c th th ng nhpPDF created with pdfFactory Pro trial version www.pdffactory.com

bng cch nhn nt gia iu khin pha trc. Cc hnh di l ti hng dn bn cch v ch bo tr hng ca mn hnh LCD Samsung 510N.

mc 0

u tin, gim sng v tng phn v mc thp nht

ri chn chc nng i (thng minh)

tip theo, nhn v gi nt enter t 10 ti 15 giy


con s ny cho bit bng v n dng bao lu ch bo tr hng mn hnh LCD Samsung 510N

y l ch bo tr hng my Samsung 510N. Bn c th th thit lp ny trn cc m-en mn hnh LCD Samsung khc.

ch bo tr hng ca mn hnh LCD Acer

203 gi

Hnh trn l ch bo tr hng ca my Acer AL1916W. Bn c th thy nhiu thng tin c ch nh mn hnh LCD dng bao lu (203 gi), s m-en bng LCD (INNO.VO), thit lp mu, v.v. Lu : Cc hng mn hnh LCD khc nhau c cch khc nhau vo ch bo tr hng. Bn c th gh forum website sa in t ca ti hi v chi tit ng nhp hoc mua sch o to mn hnh LCD c thng tin ng nhp hoc hi cc bn sa ca bn.


Khc bit gia plasma v LCD

TV plasma Samsung Bng plasma Mn hnh plasma gm hng trm ngn cha kh tr (argon, neon, v xenon) gia hai tm knh hoc nha trong sut. Vi TV plasma, bng t pht sng, do ton b mn nh cho nh sng vi mu en sm, sng ng trong iu kin nh sng phng khch thng thng. Tui th cc nguyn t phosphor TV plasma trong cc nm gn y c ko di cho thi hn thc t ln ti 60.000 gi. l tm gi hot ng mi ngy trong hn 20 nm trc khi mn nh gim sng i mt na so vi ban u. Plasma cng c li th v bo ha mu. Mi im nh cha cc phn t mu , xanh l v xanh dng ca ring n, do chng c s phi hp kt ta mu rt chnh xc. V mt k thut, phn gii b gii hn mn hnh plasma nh hn. Mi , vi cc phosphor mu , xanh l v xanh dng ca n, c vai tr nh mt im nh ring bit. ln cn thit ca cc ny c ngha ch cc mn nh plasma ln nht mi th hin c phn gii cao t nhin trung thc vi 1920 x 1080 im nh. Cc mn nh plasma gn y theo kp LCD v h s tng phn (thc o mi lin h gia mu en ti nht vi mu trng sng nht), nh cc thut ton bn trong pht trin mi y chn ngun ti cc im nh c th lc im nh ti thc s. iu ny c th cho h s tng phn ln ti 10.000:1 cc m-en mi nht. Cng ngh chn nh sng LCD qung co cn hn ch h s tng phn 1200:1, d loi dnh cho ngi tiu dng s sm vt 1600:1. iu ny c th quan trng hoc khng: tc ng i vi ngi xem cn ty theo cc nhn t b sung nh sng ton din v nh sng chung quanh. Cc th nghim cho thy rng ngay c khi nhn h s tng phn 700:1, hu ht mt ngi u hi lng vi mc r rng ca ch ti.


TV LCD Humax Bng LCD Cc LCD cha nhiu im nh hn trong mi inch vung, do chng c th t ti phn gii cao trn mn nh nh. Cc mn nh LCD s dng ma trn tinh th lng nh xu gia tm knh hoc nha trong sut, vi ma trn transistor mng mng (TFT) cung cp in p cho cc . Khi c np bng in, cc tinh th dui ra cho nh sng i qua t ngun pha sau chng. Ty gc xon, hoc trng thi phn cc, cc tinh th chn cc phn ring bit ca di mu nh sng trng pht ra ti khi chng cho mu mong mun nh qu trnh lc tr. Ngun nh sng trng c th c thay th khi n dn m, do tui th mn hnh LCD c th c ko di. Cc ci tin gn y v vt cht lm cht nn LCD cng tng gc nhn thc t ln 130 ti 140 . Mt s m-en mi nht c th t 170 , cnh tranh vi gc nhn ca hu ht cc mn nh plasma.


Dng c v thit b oDng c sa mn hnh LCD, bn cn mt s dng c gip sa mn hnh LCD nhanh chng. y l mt s dng c bn phi c gian hng chuyn mn:

nhp

Nhp - dng n gi linh kin dn nh th n s kh vut ra khi bn. Ngn tay chng ta l qu to so vi linh kin nh xu ny. Tm kim loi mng v cng - dng n d m np mn hnh LCD. ng dng tournevis thng m np LCD bi n c th li vt cy trn np nha. Tt nht l tch nhp lm hai. Mua nhp cht lng tt bi mt s nhp r kim loi c th cong khi bn c m np LCD.

knh lp

bn c th thy r linh kin dn nh knh lp

Knh lp - nu c hy mua knh phng i gp 10 c n LED sn trong knh. Dng c ny quan trng xc nh k hiu linh kin dn trn thn n. Thiu knhPDF created with pdfFactory Pro trial version www.pdffactory.com

lp, bn s kh nhn ra m linh kin dn.

vi knh phng i gp 10 c n, bn d dng c c mi m dn nh xu trn thn linh kin

Knh hin vi hai mt Nu va ti tin bn c th mua knh lp xn hn nh knh hin vi hai mt.

n hu xe hi 24V


Bng n xe hi - bn s cn n hu xe hi cch ly vn v cp ngun LCD. Mua n hu xe hi 12V v 24V nhanh chng tm ra li v vn cp ngun LCD bt k.

b tournevis nh

B tournevis nh - hu ht bng mn hnh LCD c c rt nh dng ng v bo iu khin. Bn cn b tournevis nh m c v. Hp ng i cu - bn c th dng hp ng i cu hoc hp bt k bn thy tt cho vic ct gi mi dng c nhm d ly khi cn d tm h hng v sa mn hnh LCD.

hp ng i cu vi mi dng c trong

My kh - y l dng c phi c cho vic d tm h hng mn hnh LCD. Vic tho v hn li linh kin dn cn ti cng c chuyn dng ny. Bn c bit l my kh c th gii quyt kh ch mi hn nhiu linh kin dn trong bo mch in?


Thit b o Bn cnh thit b o ti thiu nh ng h kim v s, ng h in dung s, ng h ESR, my kim flyback v my hin sng, bn cng s cn cc thit b o chuyn dng sau y d xc nh li linh kin dn. Thit b o ti ni ti l Peak Atlas Component Analyser v nhp thng minh. Vi cc my nh th chc chn bn s t tin hn trong vic sa mn hnh LCD.

Peak Atlas Component Analyser

Nhp thng minhPDF created with pdfFactory Pro trial version www.pdffactory.com

B quyt m np mn hnh LCDu bng

tch nhp ra khi ta cn n d m np mn hnh LCD

m mn hnh LCD thnh cng m khng li vt cy trn np nha, bn phi dng kim loi mt bng, rng v cng. ng dng tournevis m np bi nht nh s li vt cy su trn np nha. Np nha thc s khng cng v lc bn dng tournevis cy np, nha mm s b lm. Tht ra kim loi ny bn c th ly t nhp tch ra. ng mua nhp r bi kim loi d cong v s khng gi cht c np mn hnh LCD. Mua nhp cht lng tt v m lm hai v dng phn ui cy np. Lun bt u tho np mn hnh LCD t di. Chc chn bn tho mn hnh LCD trc khi bn m np. Nhiu c mn hnh LCD nm pha sau - do cn bit iu ny. Khi tho xong np gc di, th bn c th bt u m np cnh v cui cng l np gc trn v cnh kia. mt s mn hnh LCD, bn c th dng c hai tay (vi cht lc) tho np cnh. Nhn hnh tham kho.

mn hnh

tho v c trc khi m np mn hnh LCD


tho ht c b che trc khi m np mn hnh LCD

tho c trc khi m np mn hnh LCD

bt u t di v m gc trc

y nhp v gia v cy ra


gi ti gc kia

m xong phn di, gi ti cnh

t t nhc ln kh y xung i khi khng cn ti nhp cng m c np bng cht lc

cy np cnh t di trc


gi ti cnh trn

khi c hai cnh u nhc ln, gi kh nhc nguyn np bng cht lc

nguyn np c m. Bn cn tp nhiu m thnh cng mi kiu np mn hnh LCD


Thng hiu m in tr dn v kim tra

in tr dn

in tr dn trong mainboard

Thng hiu in tr dn l rt quan trng nu bn mun sa c mn hnh LCD. Mi in tr dn u c m s trn thn. S khng qu mt thi gian hiu n bi hng dn di s ch chnh xc cch bn c th tnh gi tr Ohm d dng. 0 = Jumper 000 = Jumper 6R8 = 6,8 100 = 10 750 = 75 101 = 100 164 = 160000 = 160K 472 = 4700 = 4,7K 1200 = 120PDF created with pdfFactory Pro trial version www.pdffactory.com

1201 =1200 = 1,2K 1001 =1000 = 1K 2000 = 200 1182 = 11800 = 11,8K 10003 = 1000000 = 1M M in tr dn tng t nh in tr mng dn. in tr mng dn tht ra gm vi in tr cng gi tr Ohm trong mt in tr n.

in tr mng dn A512 ngha l c bn in tr 5,1K (5100) trong.

Nhn bn trong ca in tr mng dn


in tr mng dn

Kim tra in tr dn Phng php kim tra tng t nh khi bn kim in tr thng (in tr than, in tr dy qun, v.v.). Tnh m in tr dn trc, khi bn c gi tr th kim bng ng h s. ng dng ng h kim bi n s khng cho s o chnh xc bng ng h s.

i khi bn c th o in tr dn trn mch. Nu bn khng o c kt qu chnh xc th tt nht vn l ht h chn v o


kim tra in tr dn

t que o vo hai u ca in tr dn trn mch v c kt qu trc tip t mn hnh LCD ng h s. i khi kim tra trn mch s khng cho s o chnh xc do bn phi tho n ra khi mch bng sng hn hoc my kh.

in tr dn c m in 330

in tr dn 330 l 33. Nh in tr thng, in tr dn cng c sai s do kt qu 32,5 l chp nhn c


Thng thng in tr dn rt mnh (t gp vn ) trong mainboard nhng khc vi bo cp ngun. Chc chn cc hng bo cp ngun mn hnh LCD s dng in tr dn v khi c vn bt k cp ngun (trc mch, ngn mch, v.v.); mt s in tr dn c th b chy! Mt khi in tr dn b chy, cch duy nht tm ra gi tr l thng qua s mch v so snh vi cng m-en mn hnh LCD. Bn c th gi cho bn sa hi xem h c cng m-en mn hnh khng tm ra gi tr ca in tr dn.


Thng hiu m t dn v kim tra

t dn in hnh trong bo mn hnh LCD Samsung

Gi tr in dung c trn thn linh kin, s dng mu thn v mt ch ci, hoc mt ch ci v mt con s. V d, t thn c ch A l t 1pF. Nu thn en c ch A, n bng 10pF. Gi tr t mch in trn Pentax

Amu thn

mu

ch ci ch ci A C E G J L N Q S A C E G J L N Q S U W Y gi tr(pF) 1 2 3 4 5 6 7 8 9 10 12 15 18 22 27 33 39 47 56 68 82

en


M hai k t chun Pentax

J3

= 2,2 x 1000 = 2200pF s nhn (0 - 9) gi tr (tra bng)

v d S2 = 4,7 x 100 = 470pF b0 = 3,5 x 1 = 3,5pF s nhn 0=x1 1 = x 10 2 = x 100 3 = x 1000 4 = x 10000 v.v.

gi tr (33 k hiu gi tr) - ch hoa v thng A 1,0 H 2,0 b 3,5 f 5,0 X 7,5 B 1,1 J 2,2 p 3,6 T 5,1 t 8,0 C 1,2 K 2,4 Q 3,9 U 5,6 Y 8,2 D 1,3 a 2,5 d 4,0 m 6,0 y 9,0 E 1,5 L 2,7 R 4,3 V 6,2 Z 9,1 F 1,6 M 3,0 e 4,5 W 6,8 G 1,8 N 3,3 S 4,7 n 7,0

t dn tantan 47F 10V

M hai k t hng Samsung Gi tr di 100pF - c trc tip Gi tr t 100pF - c theo m ch ci/s = 10 x 10 = 100pF s nhn (1 - 9) gi tr (tra bng)

05 82

= 5pF

A1

= 82pF

N3

= 33 x 1000 = 33000pF = 0,033mF s nhn 1 = x 10 2 = x 100 3 = x 1000 4 = x 10000 v.v.

gi tr (24 k hiu gi tr) - ch c ch hoa A 10 F 16 L 27 R 43 W 68 B 11 G 18 M 30 S 47 X 75 C 12 H 20 N 33 T 51 Y 82 D 13 J 22 P 36 U 56 Z 91 E 15 K 24 Q 39 V 62PDF created with pdfFactory Pro trial version www.pdffactory.com

M mt k t chun Samsung ca t chp

W (cam)

= 4,7 x 1 = 4,7pF mu - s nhn k hiu - gi tr

v d R (xanh l) = 3,3 x 100 = 330pF 7 (xanh) = 8,2 x 1000 = 8200pF

A B C D E

gi tr (24 k hiu gi tr) - ch hoa v s 1,0 H 1,6 N 2,7 V 4,3 3 6,8 1,1 I 1,8 O 3,0 W 4,7 4 7,5 J 2,0 R 3,3 X 5,1 7 8,2 1,2 K 2,2 S 3,6 Y 5,6 9 9,1 1,3 L 2,4 T 3,9 Z 6,2 1,5

(s nhn) cam = x 1 en = x 10 xanh l = x 100 xanh = x 1000 tm = x 10000 = x 100000

Cc bng m t dn trn ch ng vi tng hng. Cc nh sn xut khc c m ring do k thut vin sa cha nh chng ta gp kh khn trong vic tm ra gi tr t dn. Ch c mt cch c th tm ra gi tr t. Gi s bn pht hin ra mt t dn mu b chm trong mainboard mn hnh LCD, vic bn c th lm tip theo l tm chung quanh mch t dn cng kch thc v mu thn. Tho n ra khi mch v o gi tr t; khi bn c c gi tr bn c th thay t mi ch t dn mu b chm. Ti tng lm trc y v n c tc dng! Kim tra t dn C vi cch bn c th kim tra t dn tm thy trong bo mn hnh LCD. Cch th nht l dng thit b o chuyn dng c thit k kim tra linh kin dn nh nhp thng minh

bn c th o t dn trn mch vi ng h chuyn dng nhng thng kt qu khng chnh xc bng kim tra t ngoi mch


Kp u nhp vo t dn v bn c th c trc tip t mn hnh LCD ca nhp thng minh. Ti thy kt qu s khng chnh xc khi o t dn trn mch v bn cn ht n ra v kim tra ngui c s o chnh xc.

Kim tra t dn trn mch bng nhp thng minh Th hai, chng ta c ng h in dung s kim tra gi tr in dung t dn. c kt qu tt chng ta ht n ra v kim tra. t que o vo t dn, chn thang o in dung ph hp v c t mn hnh LCD ca ng h. Bt li duy nht khi dng cch ny kim tra t dn l que o qu to vi linh kin nh xu. D sao th khng l vn i vi k thut vin sa cha nh chng ta bi c th d dng ch li que o kim tra linh kin nh xu.

t dn

kim tra t ngoi mch o c chnh xc hn


i khi ch o gi tr in dung s khng m bo t tt hay khng v bn cn thc hin cch kim tra khc chc chn t khng b nh thng khi qu ti. Chng ta s lm nh th no? Phng php kim tra th ba s tr li bn. Bng cch dng ng h kim chnh thang x10K chng ta c th kim tra chnh xc t dn b nh thng khi qu in p chu ng. t que o vo t v kim khng c ch s o no. Nu gi tr t ln, n c th lm kim nhch cht xu v tr v v tr ban u (). o que o v o li v bn vn c kt qu c. iu ny chng t t hot ng tt! Lu : Bt k loi t dn bn o l g, kim khng c ch s o no c hai ln bn o vi ng h kim.

t dn cn tt s khng ln kim

t dn

mt s t dn kim tra tt vi ng h in dung s nhng khng kim tra c vi ng h kim. Chnh thang x10K, kim khng c ch s o no

Kt lun - xc nh c t dn cn tt, bn phi thc hin hai cch kim tra; u tin o gi tr in dung v cch kia l kim vi ng h kim chnh thang x10K v chc chn l n khng b chm.


Thng hiu m transistor v diode dn v kim tratransistor dn

IC dn

kim tra thnh cng transistor v diode dn, u tin bn cn tm hiu ngha m in trn linh kin. Diode dn 3 chn c th lm bn tng l transistor. Transistor s c th lm bn tng l transistor thng v c th. Nu bn khng bit ngha m, ti tin l bn s nhc cng kim tra. Bn c th cho linh kin tt l h v iu ny cui cng s lm mt nhiu thi gian d tm h hng hn.

bn c ngh ba linh kin dn ny l transistor khng? Tht ra chng l diode dn. Hy nhn k hiu trn bo mch in

di ch l mt s thng s m transistor v diode dn. Th trng c nhiu m v k hiu trn linh kin dn do bng ny khng th k ht m. Bn phi ghPDF created with pdfFactory Pro trial version www.pdffactory.com

website http://www.tkb-4u.com tham kho v tm cp nht bt k cho m dn. Khi bn bit m ca loi linh kin no, sau bn c th dng phng php kim tra cn thit kim.

Kim tra transistor dn Kim tra transistor dn hi khc vi transistor lng cc thng bi nhiu transistor dn c h vi transistor s m bn trong c thm in tr lm cho s o t ng h kim thnh khc hn.


Transistor s PNP (quan st hai in tr)

V SOT-323 cho transistor dn Cch duy nht kim tra l thng qua so snh v bn phi so vi transistor c cng m s trn thn.

so snh in tr c c vi mt transistor dn cn tt


Kim tra diode

Diode dn 1N4148

Diode dn loi 1N4000

kim diode dn ging vi kim diode xi-lic thng tr phi l diode Schottky

Chnh thang x10K kim diode dn Kim diode dn ging vi kim diode silicon thng. Bn phi dng ng h kim chnh thang x10K kim diode dn. Diode dn cn tt s cho mt s o v nu bn c hai s o c ngha l diode b chm. Bn cng phi l diode Schottky$ dn s cho hai s o nhng khng b chm. Xem chng ng dng chnh lu diode Schottky v kim tra bit cch kim diode Schottky.

$

tn nh vt l ngi c Walter H. Schottky


M IC in hnh mn hnh LCD

IC n p ng ra 3,3V

IC n p ngun 3,3V AIC1084-33 = n p ngun 3,3V (vo 5V) KA278R33 = n p ngun 3,3V (vo 5V) RT9164-25CG = n p ngun 2,5V LM2596 = n p ngun 5V (vo 12V) AMC2576-5 = n p ngun 5V (vo 12V) 78M05 = n p ngun 5V 78M12 = n p ngun 5V APL5522KCTR = n p ngun i: chn 1 = 3,3V, chn 4 = 2,5V (vo 5V) TDA7053A = IC khuch i m thanh TDA8227p = IC khuch i m thanh TDA7496 = IC khuch i m thanh


IC khuch i m thanh

IC n p ngun 5V LM2596

IC n p ngun 3,3V AIC1084


m s trn thn NT68F63LG ca IC mn hnh LCD Samsung

y ch l mt s v d m IC trong mn hnh LCD. L do cn mn hnh LCD mi cha c mt trn th trng, ti gi bn tm trn Internet tham kho m mi nht cho m s trn thn ca IC bt k. Bn cng c th t tm hiu linh kin ba chn c phi l IC n p hay khng nh thc hin kim tra in p. i khi linh kin ba chn c th l mosfet do lu im ny.

IC iu khin trong bo iu khin LCD

Lu : tng lai bn c th pht hin c bn IC n p trong mt IC bi hin c IC n p i trong mt IC. Ch cn tnh to v linh hot.


ng dng chnh lu diode Schottky v kim tra

diode Schottky trong cp ngun mn hnh LCD

Diode Schottky hay chnh lu chun Schottky c thit k trong chnh lu hiu sut cao cn thit cho cc ng dng nh mch cp ngun ch ngt/m (SMPS), n p ngt/m, v.v. Chc nng ca diode Schottky l i in p AC thnh DC nh th m in p DC c th dng cho cc mch khc nh CPU, EEPROM, cao p, v.v. Nu bn quan st s mch in bt k, k hiu chnh lu Schottky ging ht diode thng.

Diode Schottky in hnh Thm ch l b ngoi, hnh dng v thit k u ging diode thng. Khc bit ch yu gia diode thng v diode chun Schottky l m s trn thn. Bi b ngoiPDF created with pdfFactory Pro trial version www.pdffactory.com

ging nhau, nhiu th sa in t ngh rng o diode Schottky ch nh o diode thng. Nu bn dng phng php o diode thng kim diode Schottky th c kh nng khng gii quyt c vn . Bn cng thy rng c hai diode Schottky trong mt nh hnh di mn hnh LCD l hon ton bnh thng. Hai diode Schottky quay u vo nhau v phng php kim tra tng t nh khi o mt diode.

hai diode Schottky trong mt - quan st hai k hiu diode Schottky quay u vo nhau. Lu : mt s linh kin khng thy c k hiu

Ti s ch bn phng php ng kim diode Schottky nh th bn s khng ln ln na. Dng sch tra linh kin bn dn v cng vi c my tm kim trn mng, bn s d dng pht hin diode ang kim l Schottky, diode thng, hoc thm ch l diode m. Vi ngh sa in t, bn khng nn on linh kin ang o l g, ch cn xc nh d liu v th l 100% bn chc chn phng php no l tt nht kim tra n. Khi xc nh diode bn s kim l diode Schottky th bn phi dng cch ng o. Dng ng h kim, chnh thang x1 v t que vo chn gia v que en vo mt chn cnh, kim phi ch s o Ohm thp. Gi o que o thnh que en vo chn gia v que vo chn cnh, khng ln kim. Nu c ln kim th diode Schottky coi nh b chm. Thng th n ch b chm mt chn cnh v ti t khi thy hai diode Schottky cng b nh thng.


s o Ohm thp

gi chnh thang x1 v t que vo chn gia v que en vo chn tri v kim phi ch s o Ohm thp

s o Ohm thp

gi t que en vo chn phi v kim phi ch s o Ohm thp


khng ln kim

chnh thang x1 v t que en vo chn gia v que vo chn tri. Kim khng c ch s o no

khng ln kim

gi t que vo chn phi v kim khng c ch s o no

Gi chnh thang x10K v t que vo cc m v que en vo cc dng. Bn phi thy kim ln ht vch. Gi, o que v bn phi thy s o x xch. Ni cch khc, kim s nhch ln cht xu. y l c im tt ca mt diode Schottky khi bnPDF created with pdfFactory Pro trial version www.pdffactory.com

c s o kiu vy. Tuy nhin nu bn kim diode thng bng thang x10K v bn thy l n c hai s o th diode b li v cn c thay.

y l c im ca mt diode Schottky tt

gi chnh thang x10K v t que en vo chn gia v que vo chn tri. Kim phi ch s o in tr cao

kim phi ch s o in tr cao

bn s c cng kt qu khi bn t que vo chn phi. Kim phi ch s o in tr cao


Diode chun Schottky b chm s cho hai s o ht vch trn mt ng h. Gi s mt th sa in t khng bit cch kim tra diode Schottky, anh ta hoc c ta c th ngh s o x xch thang x10K c ngha l diode b h. i khi thay diode Schottky bng diode thng c th lm thit b khng n nh c bit vi mch nhy cm. Tt nht l thay bng diode c cng m s trn thn hoc c thng s l in p v dng in phi cao hn hoc cng thng s vi diode ban u. M s trn thn in hnh cho diode Schottky l SBL1040CT, STPR10, SB530, v.v.

bt k bn kim diode Schottky i hay diode Schottky n th kt qu vn vy

Tham kho sch thay linh kin bn dn c d liu v tm ra thng s ca m s trn thn. Nu bn c mt con, th o bng ng h kim v bn s ngc nhin l c hai s o thang x10K nhng khng phi l b chm. Xin ni lun l h hng diode Schottky hon ton bnh thng do bn phi bit mnh ang o ci g.


im nh tc v cht mn hnh LCDNu bn gp mn hnh LCD c im nh tc hoc im nh cht (mt im trn mn nh m lun sng hoc lun ti), thng l bi trc trc transistor hoc s phn b khng u ca cht lng trong mn hnh tinh th lng. Thng sa c. im nh tc l g?mn nh ti - mi im nh phi tt

im nh tc mn hnh LCD. im nh vn bt m l ra l tt

im nh tc l mt khim khuyt im nh bnh thng trn mn nh LCD. im nh tc l mt im sng mu trn mn nh pht ra mu m l ra l n khng c pht. im nh tc rt d nhn thy trn mn nh ti hoc mu en ni m n s xut hin mu , xanh l, xanh, hoc s pha trn bt k t ba mu ny k c vng, tm hoc thm ch mu trng. Mu , xanh l, hoc xanh l im nh tc thng thy nht. Nhiu ngi thng gn nhm im nh tc l im nh cht, tc mt trong ba im nh con ca n thng xuyn tt, cho im nh mu en.

im nh cht trn mn nh LCD

im nh tc l thng thy mn hnh LCD, TV LCD v cc thit b xch tay. Mi im nh trn mn nh LCD c to thnh t ba (im nh con), mu , xanh l, v xanh dng, cho mu nhn thy c ca im nh nh sng cn xng ca chng. im nh tc do khim khuyt sn xut li mt hoc nhiu c bt. im nh tc khng d nhn thy trn nn mu trng v bn cn chc chn nn phi ti (mu en) xc nh im nh tc. Gh website http://www.astris.com/dpl/ chuyn mn hnh LCD sang nn bt k bn thch.PDF created with pdfFactory Pro trial version www.pdffactory.com

Lm sao sa im nh tc? Phng php n 1. Bt mn hnh LCD v hin th nh mu en nh th bn c th d xc nh im nh tc u. 2. Dng khn m v qun khn quanh ngn tay nh th khi n vo, bn s khng lm try xc mn nh. 3. Ch n nh (xoa) ln ch c im nh tc nu khng bn c th gy thm im nh tc na. Trong khi n bn c th tt mn nh v bt li vi ln. 4. Tip tc n ln im nh tc ti khi n mt hn (i khi im nh tc c th xut hin li do bn phi lm thm vi vng) 5. Nu im nh tc vn cn th ti ngh bn phi dng n phng php phn mm.

dng ngn tay xoa nh im nh tc hoc im nh cht khng lin tc (chp chn)

Phng php phn mm

bn c th ko hnh t n ln ch c im nh tc v n chy hai gi sa im nh tc

1. Th chy phn mm sa im nh bn c th ly ti www.killdeadpixel.com. im nh tc thng c th c hot ng mnh tr li nh nhanh chng bt v tt chng. 2. Nu im nh tc vn cn thm ch sau nhiu gi chy phn mm, th n khng sa c na v cch duy nht l thay bng LCD hoc tr li khch hng mn hnh LCD. Thng thng khch hng s chp nhn bi mt hoc hai im nh tc khng nh hng lm. Nu mn hnh LCD cn bo hnh th bn phi bo nh cung cp nhng thng thng nh cung cp ch i nu c trn mi im nh tc hoc cht trn mn nh LCD!PDF created with pdfFactory Pro trial version www.pdffactory.com

im nh cht l g v lm sao sa n? im nh cht l im nh khim khuyt m vn cn ti trn mn nh LCD. im nh cht lun l mu en v d nhn thy trn nn trng. im nh cht xy ra khi transistor kch hot lng nh sng ( thy ht ba im nh con) b trc trc v kt qu l im nh mu en thng xuyn. im nh cht xut hin mu en trong khi im nh tc c th l mt mu khng i nh , xanh l hoc xanh. im nh cht thng khng sa c. Tuy nhin, bn vn c th dng phng php sa im nh tc cho im nh cht. Trc y ti gp im nh cht lc c lc khng mn hnh LCD IBM 15 v quyt nh sa n bng phng php n - chng c hi g khi th.

im nh cht trn mn nh LCD

bn c th dng knh lp nhn r im nh tc v cht

phng1. Khng c c m mn hnh LCD ra s lm mt bo hnh v nh sn xut s khng cho i. 2. Chc chn bn khng lm t thit b in no. 3. Khng c n mnh qu ln mn nh LCD bi n c th d b b (nt).


Bng LCD b nt

bng LCD b

Bng LCD nt bi nhiu nguyn nhn v hu ht l bi ri rt t bn hoc v tnh vut khi tay trong khi gi. i khi nu bn khng cn thn v lau chi bng LCD qu mnh, n cng c th nt. C cch g sa bng LCD nt? Khng ai c th sa mn nh LCD nt c. gii quyt vn bng LCD nt, tt nht l thay bng bng LCD tt. Bng LCD bn mua t bn sa hoc mua r t khch hng mn hnh LCD khng sa c do st nh bo ngun v bo scalar/mainboard.

bn phi nhn k mi thy nt nu khng bt ngun

Bn cng c th th kim trn website Ebay tm ra mn hnh LCD bt k qua s dng c bng LCD tt. Ch thay vi cng kch thc v m-en. Mt s mn hnh LCD l OEM (Original Equipment Manufacturer - nh sn xut thit b gc), vPDF created with pdfFactory Pro trial version www.pdffactory.com

d mn hnh LCD Dell ging mn hnh LCD Benq do cc bo v bng LCD ca chng c th i c!

bng LCD nt nhn gn

Thng thng nu gp bng LCD b nt ti s ra gi vi khch hng nh th ti c th tn dng cc bo bn trong (bo ngun, mainboard, bo cao p, v.v.) v thm ch l n dng sau ny. Cch ny c th tit kim nhiu v i khi ti c th sa c mn hinh LCD khch hng khc (cng m-en) nhanh chng bi ti c hng d tr nhng tt nhin l khng phi bng LCD ri.


Bng nt mn hnh LCD BENQ 15

phng!Tinh th lng c th r r t bng s c hi nu vo mt hoc ming. Nu phn da hoc phn thn th no tip xc trc tip vi bng, hy ra k. Nu c triu chng c th, hy i khm bc s.


im o in p chun mn hnh LCDim o in p chun l cch nhanh nht xc nh ch li hoc thm ch linh kin li nm u. Nhiu th sa in t chuyn nghip dng im o xc nh chnh xc. Bn s hc o in p v bt u nhn bit khu vc b li mn hnh LCD. Nguy him - trc khi bt u o im bt k mn hnh LCD, ti ht sc ngh bn nh bn sa c kinh ngim gip v chc chn dng AC l t bin th cch in (nh th mi bo v c bn phng trng hp xy ra sc in). Phi cn trng vi in v chc chn bn bit r mnh ang lm g. OK chng ta bt u! u tin xc nh cu chnh lu v sau t que o vo chn AC. Gi cht que o nh th n s khng vut v ng vo chn khc. Bi bn ang o in p AC nn khng phn bit que o.

u tin tm k hiu AC ca cu chnh lu trc khi o in p AC bng ng h vn nng

t que o vo hai chn AC cu chnh lu


in p AC phi l 230V. Ti M v quc gia no , s o khong 110V

Nu bn c s o khong 230V ( M l 110V) th chng t c in p AC t cm v cu ch ang chy. Nu n l 0V th bn phi kim mch pha trc cu chnh lu. C th h cu ch, cha bt cm, cm lng, t dy in, v.v. o in p t lc Khi bn bit cu chnh lu c ng vo cung cp AC, gi bn s o c khong 300VDC (ti M khong 150VDC) chn t lc. Chc chn l bn gi cht que o v cn thn t vo chn t. Nu bn v tnh ng trng cc chn trong khi o, n c th pht tia la in mnh v n khu vc ngun. Nu bn khng t tin lm hy nh bn sa gip . Que en phi chn m v que chn dng nh hnh. Bn c in p DC bi cu chnh lu chuyn n t ngun AC. Nu c in p DC mong mun th bn o tip in p cung cp IC cng sut, nu khng c, hy d tm h hng xc nh c vn bt k vi mch hay khng nh kh ch mi hn, t mch, v.v.

k hiu cc m t lc

bn phi o c khong 300VDC t lc khi bt ngun. Que en chn m v que chn dng


o in p cung cp (VCC) IC cng sut Ti dng bo ngun khc ch r cch o in p cung cp ca IC cng sut. u tin xc nh chn VCC ca IC cng sut nh sch tra hoc Internet. Khi bn tm c chn VCC, gi t que vo chn VCC v que en vo mass nng (chn m t lc s cp) v bt ngun. Bn phi o c in p DC t 16 ti khong 20V (ty thit k mn hnh LCD). Trong hnh di, chng ta c 16,46VDC. Nu bn o c in p ng c ngha l cu chnh lu, t lc v in tr mi ang chy v gi bn thc hin bc tip theo. ng ph thi gian khng cn thit thay cu chnh lu, t lc hoc thm ch kim tra tr s in tr mi.

t que en vo mass nng (k hiu cc m t lc) v que vo chn VCC ca IC cng sut

chc chn que o c gi cht khi o chn VCC


chc chn bn t que en vo mass nng khi o bn s cp

o in p ng ra th cp Rt n gin o. Ch cn t que vo cc m diode v que en vo mass ngui v bt ngun. Bn phi c s o l VDC mi diode ng ra th cp.diode ng ra th cp

5,14VDC t que en vo mass ngui v que vo cc m diode ng ra th cp v bt ngun. Bn phi c s o l VDC

tip theo chng ta c in p ca mt diode th cp khc l 13,68VDC


t que en vo mass ngui nu bn mun o in p bn th cp ca cp ngun

Bi bn th cp chng ta c in p ng ra ng, iu ny r rng cho bit mi linh kin bn s ca cp ngun chy tt. Nu bn b thi gian cho vic o linh kin bn ngun th bn ch ph thi gian thi. l l do v sao rt c li khi thc hin o in p bit phn no mn hnh LCD c vn . Bi c in p ng ng ra th cp, bc tip theo s l tm li pha sau cc diode ng ra th cp. o IC n p

ng ra 2,5V (2,498V) t IC n p

Nu in p ng ra tt, tip theo bn phi o in p cung cp cho mainboard. Tm IC ba chn v rt c th n l IC n p cung cp in p cho IC ca mainboard. Ch cn t que vo ng ra IC n p (thng thng chn 3 l chn ra) v c ng h. Nu n ch 2,5V hoc 3,3V th IC n p tt. Nu khng bn phi bt u d tm h hng ngc v sau t chn vo (chn 1) v i khi IC n p t n cng c th b h!


o bo cao p bo cao p hot ng, u tin IC cao p phi nhn in p cung cp (VCC) t cp ngun. in p t 12 ti 16VDC (ty thit k mn hnh LCD) v cng cp cho mch Buck Royer v bin th. Nu in p khng c hoc qu thp cho IC cao p, mn hnh LCD s khng c hnh (hnh ti) hoc thm ch l t tt chp chn. Do iu quan trng l phi chc chn rng IC cao p nhn c in p c nh t cp ngun.

hu ht mn hnh LCD u c cu ch Pico (khong 2A ti 3A) trong bo cao p

o cu ch Pico

t que vo cu ch Pico v que en vo mass ngui. c ng h v n phi l DCV. Nu in p thp hoc khng c, nghi ng h cu ch Pico v diode th cp hoc thm ch h cp ngun. i khi linh kin ngc v trc b chm (xa mch in) c th lm h in p. Ht mt chn cu ch ra v o li. Nu bn c in p bnh thng th chng t mch hoc linh kin ngc v trc c vn . Gi, gi s nu bn o c in p ng chn cp ngun IC cao p th chng t mch khi ng v mainboard chy tt. Nu bn o c 0V v cu ch Pico c khong 12 ti 16V th nghi ng mainboard b li (khng gi tn hiu on ti mch khi ng) hoc thm ch mch khi ng t n c vn .PDF created with pdfFactory Pro trial version www.pdffactory.com

o chn cp ngun IC cao p

t que vo chn cp ngun IC cao p. Chc chn bn gi cht que o

o bin th cao p

thng thng cun s c nhiu chn hn do c vi cun dy trong

thng thng cun th c t chn hn do ch c mt cun dy

bin th cao p


o bin th cao p mn hnh LCD ging nh o bin th cp ngun. Sao gi l bin th cao p? Bi n l bin th tng in p c ngha l n tng in p ng vo AC t 10 ti trn 20V thnh my trm Vn ng ra AC! C ba cch o bin th, bn c th o in tr; hoc bng my th flyback th chnh xc hn trong vic pht hin chm gia cc cun dy; hoc thm ch c th thc hin o in p.

cun s

cun th bin th cao p (bin th tng in p)

o in tr

thng thng cun s bin th c gi tr Ohm rt thp

Cun s c t vng qun hn do in tr rt thp (hu ht ng h s ch 0). Bn th c nhiu vng qun hn do in tr cao hn bn s. Ohm k ch cho bit c cun dy no trong b t hay khng v khng phi l ng h o chm gia cc cun dy. Cng chc chn rng bn chnh thang x10K o gia cun s v th. Khng c c s o no (/OL); nu c s o ngha l b chm bn trong gia cun s v th. i vi bin th b chy hoc b chm, cch duy nht gii quyt l thay bng bin th mi.


cun th c in tr cao hn bi n c nhiu cun dy hn

o cun dy b chm

kim tra cun s bng ng h th flyback s khng ln n no do c t vng qun hn

C s o in tr tt khng c ngha l bin th tt. Bn cn thc hin o cun dy b chm bng my th flyback bit cun dy thc s tt. Cun s t b chm nhng kh nng cun th l cao hn bi trong c nhiu vng qun hn. n gin l t que o my th flyback vo cun th v nhn cc n LED. Ty cun dy bin th mt s s lm sng LED u v LED 2 nhp nhy. Mt s s lm sng hai LED u v LED 3 nhp nhy v mt s s lm sng ba LED u v LED 4 nhp nhy. y l cc s o tt ca bin th cao p. Nu khng th rt c th cun dy bin th b chm.


kim tra cun s bng ng h th flyback thng sng t mt ti bn n v n cui l nhp nhy

Bn c th tm cho mnh my th flyback t website: http://www.flippers.com/pdfs/k7205.pdf o in p Php o th ba l thc hin o in p chn ra ca bin th. Bt mn hnh LCD v chnh thang ACV 1000. Gi que v o nhanh chn ca u ni backlight nh hnh. Bn c th thy r kim ng h ln rt nhanh. Bn phi nhanh chng ly que o ra nu khng mn hnh LCD s vo ch t tt bi mch hi tip pht hin ra thay i bt thng in p ng ra. Khng dng ti que en v khng cn t n vo mass ngui. Nu bn c th thy kim ln rt nhanh, y l du hiu bo bin th ang chy tt. Ngc li nu IC cao p c vn , bin th s hot ng khng mnh v bn khng th dng phng php ny o. Sau khi sa vi mn hnh LCD, ti chc bn s bit phng php no dng o bin th.

t que vo chn ra v quan st kim ng h


o tn s C cch c o kim tra bo cao p hoc bin th c ang chy khng. Ch cn t que ng h s ln thn bin th v chn php o tn s (chc chn l ng h ca bn o c thang tn s cao hn) v ng h s bt tn s. iu ny chng t bin th ang chy. Bt li ca cch ny l nu mn hnh LCD c vn t tt, ng h c th khng bt kp s o tn s.

t que ln thn bin th cao p, ng h c th bt tn hiu tn s


im o dng sng chun mn hnh LCDNh my hin sng chng ta d xc nh c vng hoc linh kin c th trong thit b in t bt k c chy hay khng. Nu bn cn cha u t ti ht sc khuyn bn mua mt ci bi vi my hin sng n c th gim bt thi gian d tm h hng. Bn c th mua my tng t hoc k thut s qua s dng v nu hp ti tin bn c th mua lun ci mi. Bn cng c th tr gi trn website Ebay. Ti khng hay dng my hin sng nhng ti phi dng n khi ti mun xem hnh ca dng sng v cng xem c dng sng mt im o c th hay khng. ng h vn nng khng th kim tra s c mt ca mt tn hiu tt v bn cn my hin sng tm ra. im o cp ngun

FET ngun dng sng ti chn G FET ngun

IC cng sut

cu chnh lu

Nh my hin sng ti c th o dng sng ra ca IC cng sut. u tin bn cn xc nh chn ra ca IC cng sut l chn no. Bn c th ly thng tin t sch tra hoc trn Internet. Ti khuyn bn tm trn Internet bi n c th cung cp nhiu chn ra ca IC i mi nht vi nhiu m s trn thn khc nhau. Sch tra c gii hn v ch cp nht ba ti bn nm mt ln. Khi bn tm c chn ra th bn c th o v xem dng sng ra. V d di, chn 8 l ng ra (cc cng - gate) bi n ti chn G FET ngun.


dng my hin sng kim tra dng sng ra ca IC cng sut

Mass my hin sng (que en my hin sng) phi ni vi mass s cp (mass nng). Ch tt nht l kp que o chn m t lc. Nu bn mun kim tra bn th th kp que o mass ngui.

khu vc ngun

k hiu cc m

kp mass my hin sng vo cc m t lc s cp


t mass my hin sng vo mass ngui nu bn mun o bn th ca cp ngun

t mass my hin sng vo mass ngui nu bn mun o bn th Lu : mass nng khc mass ngui! V d dng sng bn c khi o chn ra ca IC cng sut nh hnh di. Tt nhin mt s thit k cp ngun c th c dng sng hi khc nhng n phi l sng xung vung.

v d in hnh dng sng iu bin rng xung (MWP) ca IC cng sut

Khi bn c dng sng, ngha l IC ang nhn in p cung cp v chy tt. Nu khng c dng sng nhng c ng vo cung cp th c th do nhiu yu t nh h IC cng sut, chm FET ngun, kh ch mi hn, chm linh kin bn th ngt IC cng sut thng qua mch hi tip, li linh kin chung quanh gn IC cng sut, v.v.


im o ng ra th cp

diode ng ra th cp

o ng ra 5V v chc chn dng sng khng c gn

Nu bn mun chc c in p ng ra th cp

lcd monitor repair tieng viet unencrypted

Documents