288
Transmitter Fault Finding (40W/50W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
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
Failure to do so may result in the destruction of the PAs.
1.
Use the multimeter to measure the voltage at pin 8 of
IC301
(see
). The voltage should be:
2.
Note the current reading on the DC power supply. As mentioned in
, the current will be less than 500mA.
3.
Enter the CCTM command
332
y
(where
y
was recorded in
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
6.
If the voltage and current are both correct, go to
. If the voltage
is correct but not the current, go to
. If neither the current
nor the voltage is correct, go to
7.
Enter the CCTM command
332 1
to switch off final bias 2, and go to
.
pin 8 of IC301: < 100mV (initially)
pin 8 of IC301: 2 to 5V (after entry of CCTM 332
y
)
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...