tas 026 - dacs maintenance

GSM TAS Technical Bulletin - 026 Issue number: 01 Date: 23/12/2004 of 14

Wireless Solutions for Orange Group

GSM TAS Technical Bulletin - 026 Creation Date: 22/12/2004 Revision Date: 23/12/2004 Issue Number: 01

Impacted networks / Scope

Important Notice: The scope of the document is a combination of the subsystem, impacted software release and network information. Be aware that this information is relevant at the date where the document was issued. Due to software upgrades or new

hardware rollout, a network previously not impacted may become impacted. Please refer to https://app55.nortelnetworks.com/livelink/livelink.exe?func=ll&objId=9931757&objAction=browse&sort=namenull or contact your Customer Prime in order to get more information or to be sure to use the latest issue of this bulletin.

CENTERTEL MOBISTAR ORANGE FRANCE ORANGE NETHERLANDS ORANGE SLOVAKIA

Problem: The available NTP documentation does not adequately describe the necessary steps to maintain the DACS and LNDACS units. The Orange TAS bulletin is based on the CAB117 version 5 Impact: If proper preventive maintenance is not performed on the DACS and LNDACS, the units may malfunction which in turn can result in a loss of service during temperature extremes. Solution: Solution: This activity yields the best results if performed prior to the onset of cold weather. If any of the findings of this preventive maintenance procedure require the replacement of any part or assembly, please refer to the corresponding NTP document for that action. WARNING: IF AMBIENT AIR TEMPERATURE IS BELOW 38 DEGREES F OR 3.3 DEGREES C, THE FOLLOWING PROCEDURE IS NOT RECOMMENDED. OPENING THE DACS LID (COVER) IN LOW TEMPERATURE CONDITIONS MAY RESULT IN SYSTEM OUTAGE. ALSO, MECHANICAL CABINET INTEGRITY IS ESSENTIAL TO ENSURE PROPER CLIMATIC OPERATIONS IN UPPER AND LOWER TEMPERATURE CONDITIONS. IF THE FILTER IS NOT A NN RECOMMENDED FILTER OR RECOGNIZED

Subsystem: S8000 / S12000 outdoor

Software Release Affected:

Please consult the notice below. V14.3 / V15

Case number: 021115-58994 Key-words: DACS, LNDACS

Subject: Supplement to Nortel S8000BTS Maintenance Manual (PE/DCL/DD/0048) and Nortel S12000BTS Maintenance Manual (PE/DCL/DD/0144) Chapter 8 titled “DACS and LNDACS Technical Manual”.


EQUIVALENT AND/OR THERE ARE VOIDS WITHIN THE CABINET, (missing circuit packs, missing fillers from any location including USERICO and or bulk head plates missing or not properly secured) THIS CONDITION MAY CAUSE CLIMATIC INEFFICIENCY WITHIN THE BTS RESULTING IN IMPACTS TO PROPER SYSTEM OPERATIONS AND POTENTIAL SERVICE DISRUPTION. DACS technical information: LN DACS = NTQA97BA and NTU440AA

. NTQA97AA DACS


DACS Preventive Maintenance: First turn the DC power and then the AC power inputs to the DACS to the OFF position in this order to avoid damaging the DACS control card. FOR SYSTEMS WITH PHILLIPS/CHEROKEE/MITRA RECTIFIER SHELVES TURN THE DC POWER OFF ON THE RECTIFIER SHELF MARKED “FAN” FOR.

FOR SYSTEMS THAT HAVE HELIOS/APS RECTIFIER SHELVES, TURN THE DACS CIRCUIT BREAKER (CB2) ON THE RECTIFIER SHELF TO THE OFF POSITION.


NEXT FOR THE CABINETS THAT HAVE AN AC MAIN, TURN THE DACS AC POWER OFF (BLUE switch at the top of the AC Main marked Cooling Unit)

FOR CABINETS THAT HAVE GIPS, TURN THE DC POWER BREAKER TO THE OFF POSITION FIRST. IT IS THE BOTTOM LEFT SWITCH ON THE DCU MARKED DACS

NEXT TURN THE AC POWER SWITCH TO THE OFF POSITION. ON THE ADU. Warning: If present, the manual heater thermostat may trip due to loss of heat dissipation from fan operation. Tools Required: 1 Philips Screwdriver 1 Flathead Screwdriver 1 Multimeter 1 8 MM or possible deep 10MM well socket or deep well socket for older units 1 Ratchet 1 40cm or 5/32” Allen Wrench 1 Needle nose pliers 1 Torque tool for 40 Inch Pounds or 4.5 Newton meters use


Modulating motor and linkages – check for internal clutch release: Loosen the screw on the backside of the actuator cover and remove the plastic cover. Depress the clutch release and check for the smooth operation of the damper.

• Check that the motor rotation is not limited by the mechanical end stops on the motor. If rotation is limited

impacted by end stops, go to page 10 for damper realignment process. • Ensure the actuator arm linkage is securely attached to the actuator arm, if not, replace the actuator. • Replace the plastic actuator motor cover. Modulating motor and linkages – check for external clutch release: Depress the clutch release button (circled in the picture below) and check for the smooth operation of the damper. • Check that the motor rotation is limited by the damper position stops (damper door fully closed or fully opened)

and not by the mechanical end stops on the motor. (Note: Damper Fully Open means the damper reaches its end position lying on the base of the DACS. In some cases it could be noted the damper stops against the blowers 1-1.5 mm before reaching the base. This anomalous behavior (damper stop against blowers) does not need to be corrected not having any consequence on the DACS or BTS behavior.)

• Ensure the actuator arm linkage is securely attached to the actuator arm, if not, replace the actuator.

Screw to remove motor

Mechanical End Stop

Actuator Arm Linkage

Clutch Release


Check the brass bushing on the linkage for wear and replace if necessary.

S8000 Control Board: Examine the control board for excessive deposits of dust/salts. Remove the board, if necessary to clean. Examine the board for signs of excessive heat or cracking on any components. Examine the connecting plugs for signs of heat or cracking. If any evidence of overheating or cracking is found replace the control board. Reassemble the control board to its location within the DACS and reconnect all the plugs to the board.

Brass Bushings

P1

REG 1


OR

OR S12000 Control Board: Examine the control board for excessive deposits of dust/salts. Remove the board, if necessary to clean. Examine the board for signs of excessive heat or cracking on any components. Examine the connecting plugs for signs of heat or cracking. If any evidence of overheating or cracking is found replace the control board. Reassemble the control board to its location within the DACS and reconnect all the plugs to the board.

Blowers – check: Inspect the fan impellers and remove any debris. Check that the fan impellers are securely mounted on the fan shafts. Rotate the impellers and ensure freedom of movement. Power on the AC breaker first to avoid tripping the DC breaker, the AC DACS power breaker will be on the right side of the cabinet for all types and

P1

P7

REG1

TP1 and TP2

P7

Regulator P1

TP1 and TP2


then power on the DC breaker which is on the left hand side of the rectifier shelf. Damper check: Disconnect the plug form P1 on the DACS Control board. Note: This action will also energize the heater and should not be prolonged. Ensure that the damper fully closes. Short the two pins of P1 together. The damper will begin to open. When the damper is fully open remove the short between the two pins on P1. The damper will close. If the actuator position indicator contacts its mechanical end stop prior to the fully closed damper door position, realignment of the damper must be performed.

Damper Realignment:

To realign the damper, follow the proper power down instructions first (DC power then AC power). Next, loosen the two M5 nuts securing the damper linkage to the actuator. Position the indicator at the 3rd mark (above picture), keep the damper closed by hand (below picture) and then using a torque tool, tighten the M5 nuts on the damper

Mechanical End Stop

Actuator Arm Securing Bolts

Actuator Position Indicator


linkage to 40 inch pounds or 4.5 NM. Apply power as documented on the previous page and perform the damper check step again to ensure proper alignment of the damper is achieved. If complete damper closure (close and open positions) is still not correct, perform the damper realignment step again.

Damper Timing: If Opening time is <10s or Closing time is >30s, the actuator may malfunction prior to the next scheduled maintenance interval (i.e. 1 year). If this is the case and the system is located in a geographical region in which winter temperatures fall below 14 degrees F or -10 degrees C, it is recommended to replace the actuator motor to avoid a possible operation impact during extreme cold temperatures. Heater – check (manual reset thermostat):

While P1 is removed the heater circuit will be enabled. Ensure the YELLOW LED is illuminated. If the LED is not illuminated isolate the defective part of the heater circuit. • For manual resetting Heater Thermostats, ensure that the thermostat is set. To set the thermostat depress the

RED button. If it is set, measure across the leads to ensure it is not open. If it is found to be defective replace the heater thermostat.

• Measure the resistance of the heater coil. The coil should measure 21Ω. If it does not measure the correct value, replace the heater coil or the DACS.

• If the heater thermostat and heater are found to be good, replace the control board. Heater – check (auto reset thermostat) • For auto resetting Heater Thermostats, measure across the leads to ensure it is not open. If it is found to be

defective replace the heater thermostat. NOTE: If performing this activity in cold weather conditions or for an extended period of time, this activity may cause the thermostat to trip and will cause the Yellow LED to go out. This can be verified at the NOC if they see a

HRS Breaker Switch


DACS Fail minor alarm. If it is tripped, the heater coil cannot be measured and the heater check cannot be completed until the thermostat has reset. • Measure the resistance of the heater coil. The coil should measure 21Ω. If it does not measure the correct

value, replace the heater coil or the DACS. If the heater thermostat and heater are found to be good, replace the control board. Reconnect the P1 to the control board. All LED’s on the control board should be illuminated. Control Board – adjustment: Connect a test meter to positions TP1 and TP2 on the control board. Verify the output is 24 Vdc. If the measurement is not correct, adjust REG1 until 24 Vdc is measured. Damper/Heater Thermistor Alignment: Ensure the damper/heater thermistor is correctly positioned. The bottom of the thermistor should be positioned to be centered in the sensor window on the left side of the DACS. If the sensor is out of position carefully reposition the sensor. If the sensor is not seen and cannot be repositioned, the DACS unit should be removed to access the thermistor and reposition it or replace the DACS unit.

Blowers – operation: Check that the blowers are running smoothly and that the bearings are not making excessive noise. On the Low Noise DACS, NTQA97BA, NTQA97AB and NTU440AA, remove P7. The blower should increase to a higher speed. If a motor does not increase in speed, swap the motor input cables to verify the fault is either the control board or the motor. Reconnect P7. Blowers deemed faulty should be replaced.

Damper/Heater Thermistor


New Control Board Switch Settings for S8000 and S12000 DACS operations

S8000 DACS LN NTQA97BA & NTQA97AB (with speed control) : control board NTU498AA:

ON

1 2 3 4 5 6 7 8 9 101 3

12

ON

H1

Sw2 Sw1 H1 in position 2 Sw2 1 and 9 ON, all others OFF Sw1 normally 2 ON and 1,3 OFF

S12000 DACS NTU440AA: control board NTU498AA:

ON

1 2 3 4 5 6 7 8 9 101 3

12

ON

H1

Sw2 Sw1 H1 in position 2 Sw2 6 and 9 ON, all others OFF Sw1 normally 2 ON and 1,3 OFF


Damper/Heater and Motor Speed Thermistors – verification:

The two thermistors resistance varies by temperature. The Damper/Heater Thermistor samples the internal cabinet temperature, whereas the Motor Speed Thermistor samples the air temperature of the ambient air entering the DACS Unit. To verify the thermistors measure the resistance of each sensor. The chart below indicates the temperature to resistance values.

Thermistor Characteristics (Rt vs. T)

T

(deg.C) Rt

(k.ohm) T

(deg.C) Rt

(k.ohm) T

(deg.C) Rt

(k.ohm) 0 32.65 1 31.03 16 15.00 31 7.721 2 29.50 17 14.32 32 7.402 3 28.05 18 13.68 33 7.097 4 26.69 19 13.05 34 6.807 5 25.39 20 12.49 35 6.650 6 24.17 21 11.94 36 6.266 7 23.02 22 11.42 37 6.014 8 21.92 23 10.92 38 5.774 9 20.88 24 10.45 39 5.544

10 19.90 25 10.00 40 5.325 11 18.97 26 9.572 41 5.116 12 18.09 27 9.165 42 4.915 13 17.26 28 8.777 43 4.724 14 16.46 29 8.408 44 4.541 15 15.71 30 8.056 45 4.367

The temperature, for any given Rt, may be calculated from the following equation:

T = 1 / [A + B(ln(Rt)) + C(ln(Rt))3] – 273.15 °C

where, for the thermistors used, the constants A, B & C are:

A = 1.129241 x 10-3; B = 2.341077 x 10-4; C = 8.775468 x 10-8


The DACS part cross reference table be used to order replacement parts.

Items in the previous list with the specific order type ‘FRU’ should be supported by the Repair and Return organization. All others will require contacting the Nortel Networks sales engineer for your account or the Nortel Networks customer service representative to acquire the replacement material.

Replacement

NTQA97AA NTQA97BA & NTQA97AB NTU440AA ITEM LIEBERT

P/NCPC code PEC PEC Order

Type

x Not applicable Not applicable Blower L24326-00 A0723137 NTQA98BA NTQA98EB (kit) FRU

x x x Blower with speed control L28564-00 A0832107 NTQA9802 01 NTQA9802 FRU

x x x Blower with speed control L40028-00 A0832107 NTQA9802 02 NTQA9802 FRU

x x Not applicable

Blower cable adaptater L29690-01 A0784516 NTQA9803 NTQA9803 SRU

x Not applicable Not applicable transformer L24348-00 A0724332 QTK710BH NTQA98DB FRU

x x x transformer L24349-00 A0785383 NTQA98DB NTQA98DB FRU

x x x Actuator L24325-00 A0724282 NTQA98DA NTQA98DA FRU

x Not applicable Not applicable control assembly L24312-00 A0723751 NTQA98EA NTU498AA FRU

x x Not applicable

control assembly with speed control L28569-00 A0785386 NTQA9801 NTU498AA FRU

x x x control assembly with speed control L84140-00 A0994379 NTU498AA NTU498AA FRU

x x x Capacitor L24334-00 A0723678 NTQA98GA NTQA98GA SRU

x x x air filter L24304-00 A0724343 NTQA98AA NTQA98AA FRUP

x x x thermistor L24337-00 A0723679 NTQA98FA NTQA98FA SRU

Not Applicable x x thermistor L28565-00 A0785385 NTQA98FB NTQA98FB FRU

x x x filter switch A0724338 NTQA98HA 01 NTQA9804 (kit) SRU

x x x filter switch A0724338 NTQA98HA 02 NTQA9804 (kit) SRU

x x x Heater L24305-00 A0724340 NTQA98JA NTQA98JA SRU

x x x Thermostat L24338-00 A0724335 NTQA98KA NTQA81AA (kit) BP

x x x Thermostat (autoreset) H-0451 A0520118 NTQA8111 NTQA8111 SRU

x x x bush brass L24328-00 P0877667 NTQA98LA NTQA98LA SRU

DACS PEC Item could be found at Site


Retirement: When the bulletin information is incorporated into the NTP for V15

- End of document -

tas 026 - dacs maintenance

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