Tait TB8100 Service Manual page 151

Task 1 —
Check Alarms
Task 2 —
Check DC Supplies
Task 3 —
Check Voltage
Levels
TB8100 Service Manual
© Tait Electronics Limited September 2006
1. Set up the test equipment as shown in
PA) or Figure 8.9 on page 150
2. Run the Service Kit and connect to the base station.
3. Once connected to the base station, ensure it is in Run Mode.
4. Key the PA using the TX KEY switch on the CTU.
5. Select Alarms > Current Alarm Status and check there are no supply
voltage or temperature alarms. If there are, go to
If there are no alarms, go to
1. Measure the filtered DC supply to the control board at pin 2 or pin 3
of SK101. The voltage should be 28V ±2V. If it is, go to
it is not, go to "6W Board" on page
2. Check that the regulated supply output voltages are present at the
following test points:
TP100 +5V (digital circuitry)
TP102 +10V
TP103 –3V
If they are all present, go to
to "6W Board" on page
1. Measure the RF-DET voltage at pin 2 of SK102. The voltage should
be less than 0.8V. If it is, go to
on page 155.
2. Measure the PA-KEY-COAX voltage at pin 3 of SK102. The voltage
should be less than 0.5V. If it is, go to
Board" on page
3. Measure the scaled voltage supply at TP206. The voltage should be
1.5V to 2.45V (1.96V typical). If it is, go to
replace the control board.
4. Measure the POWER-LEVEL voltage at TP204. The voltage should
be between 0V and 4.5V, depending on the rated output power of
the PA. If it is, go to
5. Measure the KEY-CONT voltage at TP211. The voltage should be
greater than 4V. If it is, go to
board.
6. Measure the DRIVER-BIAS-MICRO voltage of the driver
transistor at pin 3 of SK103. The voltage should be 3.37V (typical).
If it is, go to Step
greater than 0V, but less than 3.37V (typical), go to
page 155.
(12V PA).
Task 2.
155.
Task 3. If one or more is not present, go
155.
Step 2. If it is not, go to
Step
155.
Step 5. If it is not, replace the control board.
Step 6. If it is not, replace the control
7. If it is 0V, replace the control board. If it is
Power Amplifier Fault Finding
Figure 8.8 on page 149
Task 3 on page
Step
"6W Board"
3. If it is not, go to
Step 4. If it is not,
"6W Board" on
(28V
139.
2. If
"6W
151