TM8100 Mobile Radio
Service Manual
Diagnosis of Faults on Main Board
185
May 2004 © Tait Electronics Limited
Task 1 —
Initial Checks
First check that the digital board or a power supply is not the cause of
the fault:
1.
Check the lock-detect signal on each side of L102 [at 1J2/1D7].
(See
.) When the circuit is functioning properly, the
lock-detect signal is active (about 3 V) to match the lock status
111
or
110
. When there is a fault and the lock status is
011
or
010
, the
lock-detect signal should be inactive (about 0 V). If it is, go to
Step 3. If it is not, go to Step 2.
2.
Check L102, check for shorts and other faults near L102, and
check the signal
SYN
LOCK
at pin 14 of IC503 [at 5H7] (see
and
). If no fault is found, the digital board
is faulty; return to
and replace the complete main-
board assembly. If there is a fault, repair it, confirm the removal
of the fault, and return to
. If the repair failed,
return to
and replace the complete main-board
assembly.
3.
Check the 6 V output from IC606 [at 6E3/6C4] (see
If the voltages are correct, go to Step 4. If they are not, check that
the logic setting at pin 1 of IC606 is 9 V, check the 9 V output
from the regulator, and check IC606 itself. If a fault is found,
repair it and confirm the removal of the fault; then enter the
CCTM command
72
again and take the action indicated. If the
repair failed or no fault could be found, return to
and replace the complete main-board assembly.
4.
Check for 3 V DC on pins 7, 15 and 16 of IC503 [at 5H7] (see
). If there is, go to Step 5. If there is not, check for
faults in the
+3
V
0
AN
supply to IC503 from IC603 [at 6H5/6D7].
If a fault is found, repair it and confirm the removal of the fault;
then enter the CCTM command
72
again and take the action
indicated. If the repair failed or no fault could be found, return to
and replace the complete main-board assembly.
5.
Check the VCL supply at C531 [at 5F0/5B5] (see
should be about 14 V DC. If it is, go to Step 6. If it is not, check
the SMPS circuit based on Q500 [at 5A1/5C1] and Q502 [at
5D1/5B3] (see
). If a fault is found, repair it and
confirm the removal of the fault; then enter the CCTM command
72
again and take the action indicated. If the repair failed or the
fault could not be found, return to
and replace the
complete main-board assembly.
6.
Check that the
DIG
SYN
EN
line at R104 [at 1J2/1D7] is active (see
). If it is, go to Task 2. If it is not, check R104, and
check for shorts and other faults near R104. If no fault is found,
the digital board is faulty; return to
and replace the
complete main-board assembly. If there is a fault, repair it,
confirm the removal of the fault, and return to
the repair failed, return to
and replace the
complete main-board assembly.
Summary of Contents for TM8000 Series
Page 32: ...32 Introduction TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Page 78: ...78 Circuit Descriptions TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Page 106: ...106 General Information TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
Page 124: ...124 Servicing Procedure TM8100 Mobile Radio Service Manual May 2004 Tait Electronics Limited ...
