TP9100 Service Manual Transmitter Fault Finding 223
© Tait Electronics Limited May 2005
Tas k 2 —
5V Power Supply
If the 7.5V power supply is correct, check the 5V 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 +5
VTX supply voltage under the TX CONTROL BOT can
(see Figure 10.3).
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 Ta s k 3
. If it is not,
the 5V regulator IC600 and the associated switching circuitry are
suspect; go to Ta s k 4
of “Power Supply Fault Finding” on page 156.
supply +5V TX: 5.0V DC
Figure 10.3 Measuring points under TX CONTROL BOT can (bottom side) for checking the +5V TX supply
DTXINH test point
TX INH test point
Measuring point for +5V TX
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