TM8100/TM8200 Service Manual
Transmitter Fault Finding (>25W)
329
© Tait Electronics Limited
November 2007
Task 31 —
Check Power at
Directional Coupler
If, as determined in
Task 26
to
Task 30
, there is no fault in the initial RF
signal path, investigate the final signal path. This part of the circuitry may
also require investigation following certain checks in
“Transmitter RF
Power”
. Begin by checking the directional coupler as follows:
1.
If not already done, remove the
DIRC
TOP
can.
2.
Remove the coupling capacitors
C348
,
C349
and
C350
for the VHF
and UHF bands or
C350
for the K5 band (see
Figure 11.26
).
3.
Solder one terminal of a 1000pF (VHF) or 82pF (UHF), or 47pF (K5
band) test capacitor to the PCB at the point shown in
Figure 11.26
.
Mount the capacitor vertically. Use a test capacitor of the type
GRM111, DLI C17, ATC 100B, or the equivalent.
4.
Solder a 50
Ω
test lead to the PCB: Solder the outer sheath to the test
pad shown in
Figure 11.26
, and solder the central wire to the other
terminal of the test capacitor.
5.
Connect the test lead to the test set.
6.
Enter the CCTM command
326 5
to set the transmitter power level
to the maximum.
7.
Enter the CCTM command
101
x x
0
, where
x
is the lowest
frequency (in hertz) for maximum power, as given in
Table 11.8
(B1),
Table 11.9
(G2),
Table 11.10
(H5),
Table 11.11
(H7), or
Table 11.12
(K5).
8.
Enter the CCTM command
33
to place the radio in transmit mode.
9.
Measure the RF output power. This should be:
10.
Enter the CCTM command
32
to place the radio in receive mode.
11.
Enter the CCTM command
101
x x
0
, where
x
is the highest
frequency (in hertz) for maximum power, as given in
Table 11.8
(B1),
Table 11.9
(G2),
Table 11.10
(H5),
Table 11.11
(H7), or
Table 11.12
(K5).
12.
Repeat
Step 8
to
Step 10
.
13.
If the power in both the above cases is now correct, go to
Step 14
.
If it does not, go to
Task 32
.
14.
Remove the test lead and test capacitor, resolder the coupling
capacitors in position, and go to
Task 33
.
RF output power: more than 70W (VHF)
more than 60W (UHF)
more than 52W (700MHz)
more than 58W (800MHz)
Summary of Contents for TM8100 mobiles
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 05 Issue 5 November 2007...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 12: ...12 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 20: ...20 Introduction TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 64: ...64 Description TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 106: ...106 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 134: ...134 General Information TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 168: ...168 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 464: ...464 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
