TM9100 Service Manual
Frequency Synthesizer Fault Finding
205
© Tait Electronics Limited
August 2005
Task 27 —
Check Transmit
Buffer Amplifier
If no transmit frequency is detected but the switching network is not faulty,
check the transmit buffer amplifier. If the amplifier is not faulty, there might
be a fault in the transmit VCO that was not detected earlier.
1.
Remove the
VCO
BOT
can.
2.
Check the transmit buffer amplifier in receive mode: Enter the
CCTM command
335 0
to set the transmit-receive switch off.
3.
Measure the voltage at pin 6 of Q5001 (see
Figure 9.10
).
4.
Then check the transmit buffer amplifier in transmit mode: Enter the
CCTM command
335 1
to set the transmit-receive switch on.
5.
Again measure the voltage at Q5001.
6.
If the voltages are correct, the transmit VCO is suspect; go to
Step 7
.
If they are not, the transmit buffer amplifier is suspect; go to
Step 9
.
7.
Remove the
VCO
TOP
can.
8.
Check the transmit VCO circuitry based on Q510 (see
Figure 9.9
).
Conclude with
Step 10
.
9.
Check the buffer circuitry based on Q5001 (see
Figure 9.10
).
10.
If a fault is found, repair the circuit, and confirm that the voltages are
now correct. If they are, go to
“Final Tasks” on page 147
. If they are
not, or if no fault could be found, replace the main-board assembly
and go to
“Final Tasks” on page 147
.
pin 6 of Q5001: 0 V DC (receive mode)
pin 6 of Q5001: 0.7
±
0.1 V DC (transmit mode)
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...