Tait TM8235, Руководство по обслуживанию

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432 Fault Finding of Control Head with 1- 2- or 3-Digit Display TM8100/TM8200 Service Manual
© Tait Electronics Limited June 2006
15.1 Display Faulty but not LEDs
Elastomeric Strips
Faulty
If all the LEDs function correctly but the display functions only partially or
not at all, first check the elastomeric strips:
1. Disconnect the control-head loom from the control head. Remove
the control-head board.
2. Remove the elastomeric strips and check the conductors in the strips
for continuity. Replace the strips if they are faulty.
3. Ensure that the conductors along the edges of the strips are clean.
Use isopropyl alcohol and a soft lens-cleaning cloth to clean the
edges.
4. Use isopropyl alcohol and a soft lens-cleaning cloth to clean the pads
for the LCD on the control-head board.
5. Insert the elastomeric strips in their slots in the space-frame.
6. Re-assemble the control-head board.
7. Reconnect the control-head loom to the control head and test the
user interface. If the fault has been removed, return to
“Initial Tasks”
on page 149 . If it has not, replace the LCD as follows.
LCD Faulty
If the elastomeric strips are not the cause of the fault, replace the LCD:
1. Disconnect the control-head loom. Remove the control-head board
and disassemble the control head.
2. Remove the LCD.
3. Use isopropyl alcohol and a soft lens-cleaning cloth to clean the
electrical contact points on the spare LCD. Carefully remove the
protective plastic film from the LCD. Take care not to scratch the soft
polariser material on both sides of the LCD.
4. Re-assemble the control head.
5. Reconnect the control-head loom and test the user interface. If the
fault has been removed, return to
“Initial Tasks” on page 149 . If it has
not, go to Step 6 .
6. The control-head board is suspect. Level-1 service centres should
replace the board. Level-2 service centres should attempt to repair the
board as follows.