368
Transmitter Fault Finding (25W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 28 —
Output of PA Driver
If the exciter output is correct, check the output of the PA driver at the
drain of Q306. If necessary, also check the signal at the gates of the PAs
Q309 and Q310. This is the last point in the initial RF signal path.
1.
With the radio still in transmit mode, measure the RF voltage at the
drain of
Q306
(A4, B1, C0) or after
C317
and
C389
(D1, H5, H6)
(see
). (Use an RFP5401A RF probe or the equiva-
lent.) The required voltage should be as given in
(B1),
(C0),
(D1) or
(H5, H6).
2.
Enter the CCTM command
32
to place the radio in receive mode.
3.
If the voltage measured above is correct, go to
. If it is not, go
4.
Check the components between
C301
and
Q306
(see
).
5.
If the above checks reveal a fault, go to
. If they do not, go to
“Biasing of PA Driver and PAs” on page 342
6.
Repair the fault. Confirm the removal of the fault and go to
. If the repair failed, replace the board and go to
7.
If not already done, remove the
PAF
TOP
can.
8.
Enter the CCTM command
326 5
to set the power level to the
maximum, and then the command
33
to place the radio in transmit
mode.
9.
Measure the RF voltage at the gates of the PAs
Q309
and
Q310
(see
).
10.
Enter the CCTM command
32
to place the radio in receive mode.
11.
If an RF voltage is present, there is no fault in the initial RF signal
path; go to
. If there is no RF voltage, go to
12.
Check the components of the interstage matching circuitry between
the PA driver
Q306
and the gates of the PAs
Q309
and
Q310
(see
).
13.
If a fault is found, repair it, confirm the removal of the fault, and go
to
. If the repair failed or the fault could
not be found, replace the board and go to
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...
