Tait TB8100 Service Manual page 164

Task 4 —
Check Output
Power
Table 8.3 Test point voltages on the 60W board
Test Point Pin
SK100/ 1
SK101
2
3
4
P102
TP1
TP2
164 Power Amplifier Fault Finding
This task assumes that:
you have calibrated the PA bias and the final calibration was successful
you have verified that Tx Key is working correctly (refer to
on page 155)
you have verified that the 6W board is operating correctly.
1. Check that the PA is set to its rated output power (i.e. 5W, 50W, or
100W according to model).
2. Put the base station in Run Mode and key the PA using the TX KEY
switch on the CTU.
3. Check that the output power shown on the RF power meter is
correct. If it is, go to
the voltage at TP1. The voltage should be 1.25V to 2.25V. If it is,
go to "Low Pass Filter and Directional Coupler Board" on page
If it is not, replace the 60W board.
Pin Name Voltage
final current 1.25V to 2.25V
FINAL_BIAS 4.0V to 4.2V
final temperature digital
ground
DC input voltage 28V
final current 1.25V to 2.25V
final bias 3.5V to 3.8V
"Final Tasks" on page
Notes
typical voltage when transmitting at rated
power;
current = measured voltage × 2
typical voltage when keyed on
digital signal, 0V and 5V
ground
filtered supply
typical voltage when transmitting at rated
power;
current = measured voltage × 2
typical voltage when keyed on
© Tait Electronics Limited September 2006
"6W Board"
170. If it is not, measure
165.
TB8100 Service Manual