Honeywell TA3840 Maintenance Manual page 17

TA3840C Communication unit
Observation
No display, indicator
5 Vdc off, despite power
supply switch on
and
No display or display erratic, despite indicator 5
Vdc on.
Some key on keyboard inefficient.
Some indicators inefficient : communications in
order and Rx or Tx not flashing, system fault on
display and indicator not flashing, display in order
and 5 Vdc indicator not lit.
Erratic working, no communication with all sensors,
no communication with external application.
Communication fault
message for all radars
and
Communication fault message for some radars.
Doc No: MM5008E – Revision 6 – ENG
green LED 24 Vdc main
input off,
green LED 24 Vdc main
input on,
green LED 24 Vdc main
input on, power supply
board's fuse not blown out.
sensor port Tx flashing
but not Rx,
no sensor port
indicators flashing.
Likely cause
- 24 Vdc Power supply not
connected on TA3840C.
- Power supply board's fuse
blown out.
- Power supply board out of
service.
- Ribbon cable connectors
badly engaged on LCD
display or CPU board.
- LCD display board out of
service.
- Ribbon cable connector from
front face badly engaged on
CPU board.
- Front face keyboard out of
service.
- Ribbon cable connector from
front face badly engaged on
CPU board.
- Front face indicators out of
service.
- Not correct operation.
- Wrong digital connection with
TA3840S rack.
- CPU board out of service.
- No communication through
TA3840S rack for some
channels.
Data Processing Racks
TA3840 Maintenance Manual
Remedy
- Check the presence of the
24 Vdc on the terminal block
on rear face.
- Check the EMC filter.
- Replace the fuse F1 on
power supply board (*).
- Replace the power supply
board (*).
- Check that the ribbon cable
connectors are well engaged.
- Replace the LCD display
board (*).
- Check that the green ribbon
cable connector is well
engaged on CPU board.
- Replace the front face (*).
- Check that the green ribbon
cable connector is well
engaged on CPU board.
- Replace the front face (*).
- Replace the CPU board (*).
- Check and secure the cable
of interconnection with
TA3840S rack.
- Refer to TA3840S rack
troubleshooting.
- Replace the CPU board (*).
- Refer to TA3840S rack
troubleshooting.
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