278
Transmitter Fault Finding (50W/40W Radios)
TM9100 Service Manual
© Tait Electronics Limited
August 2005
Task 16 —
Check Biasing
of Second PA
If the biasing of the first PA is correct, check that of the second PA (Q309).
Important
Ensure that the current limit on the DC supply is 3A.
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 pin 8 of IC301
(see
Figure 11.11
and
Figure 11.12
). The voltage should be:
2.
Note the current reading on the DC power supply. As mentioned in
Step 7
of
Task 12
, the current will be less than 500mA.
3.
Enter the CCTM command
332 y
(where
y
was recorded in
Task 12
).
4.
Check that the voltage changes to:
5.
Also note the current reading. This should increase by an amount
approximately equal to the offset given in
Table 11.6
.
6.
If the voltage and current are both correct, go to
Step 7
. If the voltage
is correct but not the current, go to
Task 17
. If neither the current
nor the voltage is correct, go to
Task 18
.
7.
Enter the CCTM command
332 1
to switch off final bias 2, and go to
Task 19
.
pin 8 of IC301: < 100mV (initially)
pin 8 of IC301: 2 to 5V (after entry of CCTM 332
y
)
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 ...