www.wepindia.com

Guidelines

As you all know that DMP consists of three major segments

Print head Segments Carriage Segment Logic card

This presentation will guide you how to identify that which segment on DMP is having issue and will help you find out the faulty components among this .

www.wepindia.com

THREE BASIC THINGS TO BE TESTED

PH coil : coils resistance has to be verified against the

specified value.

Head cable : end to end connectivity and cross

connectivity has to be checked.

Drive transistors: should be checked for transistor short

in printer off condition.

www.wepindia.com

Problem Isolation procedures

on DMP

www.wepindia.com

Print head Coil checking for 9 pin

PH Coil Resistance 14.8

Thermistor Resistance 9 K

2

1

CSX 450 Print head is having 14pin

connector (pic shows the Solder side of

the Connector).

Common Points 2,8, & 14

Thermistor Points 7& 9

With respect to Pin 2 (Common Point)

check

Pin no 1, 3 & 5

With respect to Pin 8 (Common point)

check

Pin no 4,6&13

With respect to Pin 14 (Common point)

check

Pin no 10,11 &12

14

13

www.wepindia.com

LX 540 PH check

121Pin no 1 is open

Common points -7&8 ,both

are short.

So all other pins except 1should

be measured w.r.t these

Common points

Coil resistance is 18 ohms

www.wepindia.com

Test Matrix for 9 Pin Print head

10,11&1214

4,6 &138

1,3 & 52CSX 450,

LX 800 DX,

EX330+DX

Resistance

in ohms

15 +/- 1

Pins to be

checked

Common

points

MODEL

www.wepindia.com

24 PIN print head coil check

Lq dsi 5235 PH

LQ DSI 5235 Print head is having 15

&17pin connector (pic shows the

Solder side of the Connector).

For 17 pin connector

Common Points 2,8, 10& 16

Thermistor Points 1& 5

Since all common points are shorted

in 24 pin PH can check all pins with

respect to any of these common pin

For 15 pin connector

Common points 7&8

Coil resistance-14+/-10%

Lq dsi 5235 WeP PH

1

1

2

2

17

15

LQ DSI 5235 PH

www.wepindia.com

Test Matrix for 24 pin PH

25 +/- 17,8&9all6,7&8LQ 1050+DX

19 +/- 17&8All except

7&8

12,13&14all10,11 &12HQ 1070+DX

25 +/- 17&8All except

7&8

12,13&14all10,11 &12DSI 810

17 +/- 11&5All except

1&5

2,8,10&16all7&8LQ DSI 5235

ThermistorPins to be

checked

CommonPins to be

checked

Common

Resistanc

e in ohms17Pin connector15 pin connectorModel

www.wepindia.com

PH Drive (Transistor) check for 24 pin

Here 1 & 10 are collector

2,4,6,8 are base

1,3,5,7 are emitter

www.wepindia.com

Driver Transistor checking for 9pin

Check whether

emitter and collector

are shorted by

checking connectivity

between them.

www.wepindia.com

Head Cable Checking

1.CHECK adjacent pins

there should not be

any connectivity

between them

Adjacent pins

www.wepindia.com

Checking of end to end connectivity

Check end to end connectivity of each line by placing probe at the

same pins on either ends of cable

EX: pin marked 1 at both ends pf cables should be checked in below fig.

1

1

www.wepindia.com

Procedure for carriage

Check whether carriage is moving freely

using hands without applying much force.

Check whether Ribbon drives moving

without any struck manually.

Check whether Home position sensor is

working fine

Check CR motor

Finally check logic card driver transistors

www.wepindia.com

Procedure to check CR motor

There are 6 pins and four coil in CR motor

1 & 2 are common points

1 is common for 5 &6

2 is common for 3&4

Measure the coil resistance of each pin W.R.T their common points

16

www.wepindia.com

Chart of coil resistance for each

models

15 ohmsLX 540+DX,LQ 540+DX

7.6 ohmsEX 330+DX ,HQ

1070+DX,800 DX, LQ 1050

+DX Super

DSI810

4.6 ohmsLQDSI 5235,CSX450

Coil resistance Model