Tait TM8100 mobiles, Service Manual

Page: 276 / 620

276 Transmitter Fault Finding (>25W) TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
Task 3 —
9V Power Supply
If the supply from the power connector is correct, check the 9V DC supply.
1. Enter the CCTM command
326 1
to set the transmitter power level
very low.
2. Enter the CCTM command 33 to place the radio in transmit mode.
3. Measure the supply voltage between the
9
V
0
TX
test point and the
GND
test point (see Figure 11.4 ).
4. Enter the CCTM command
32
to place the radio in receive mode.
5. If the supply measured in Step 3 is correct, go to Task 4 in
“Transmitter RF Power” on page 278 . If it is not, the 9V regulator
IC601 and the associated switching circuitry Q603 are suspect; go to
Task 3 of “Power Supply Fault Finding” on page 174 .
supply 9V0 TX: 9.0
±
0.5V DC