Tait TM8100 mobiles Service Manual page 366

Task 15 —
Shaping Filter for
Power Control
366 Transmitter Fault Finding (25W)
If neither the voltage nor the current measured in
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 331 x, do not
specify a value x higher than that recorded in
Failure to do so might result in the destruction of the PAs.
1. Use the multimeter to measure the voltage at the
(see Figure 12.8). The voltage should be:
FIN1 test point: 18 ± 2mV (initially)
Enter the CCTM command 331 x (where x was recorded in
2.
3. Check that the voltage changes to:
FIN1 test point: 1.1 to 2.7V (after entry of CCTM 331 x)
Enter the CCTM command 32 to place the radio in receive mode.
4.
5. If the voltage measured above is correct, go to
to "CODEC and Audio Fault Finding" on page
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
replace the board and go to
"Final Tasks" on page
"Final Tasks" on page
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
Task 13 is correct, then
Task 12.
1 test point
FIN
Task 12).
Step 6. If it is not, go
399.
163. If the repair failed,
163.