TM8100/TM8200 Service Manual Transmitter Fault Finding (25W) 351
© Tait Electronics Limited June 2006
Task 18 —
Shaping Filter for
Power Control
If neither the voltage nor the current measured in Task 16 is correct, then
the shaping filter for the power-control circuitry or the CODEC and audio
circuitry is suspect.
Important Ensure that the current limit on the DC supply is 2A.
And, when entering the CCTM command 332 y, do not
specify a value y higher than that recorded in Task 12.
Failure to do so might result in the destruction of the PAs.
1. Use the multimeter to measure the voltage at the
FIN2 test point
(see Figure 12.8). The voltage should be:
2. Enter the CCTM command 332 y (where y was recorded in Tas k 12
).
3. Check that the voltage changes to:
4. Enter the CCTM command 32 to place the radio in receive mode.
5. If the voltage measured above is correct, go to Step 6. If it is not, go
to “CODEC and Audio Fault Finding” on page 381.
6. Check IC301 and the surrounding shaping-filter circuitry
(see Figure 12.8). If a fault is found, repair it, confirm the removal
of the fault, and go to “Final Tasks” on page 157. If the repair failed,
replace the board and go to “Final Tasks” on page 157.
FIN2 test point: 18 ± 2V (initially)
FIN2 test point: 1.1 to 2.7V (after entry of CCTM 332 y)
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