Tait TP9100 - Page 262

262 Receiver Fault Finding TP9100 Service Manual
© Tait Electronics Limited May 2005
Task 11 —
FE Tune BPF Settings
If the AGC voltage calibration is correct, check the FE tune BPF settings.
1. Note the settings listed in the “FE Tune BPF Settings” field.
The nominal settings should be as listed in Table 11.2.
2. If the settings are correct, go to Task 1 2
. If they are not, go to Step 3.
3. Recalibrate the receiver and check the settings again.
4. If the settings are now correct, go to Step 5. If they are not, go to
Ta sk 1
and check the receiver sensitivity.
5. Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 134. If it has not, go to Tas k 12
.
Task 12 —
RSSI Delta Gain
If the FE tune BPF settings are also correct, check the RSSI delta gain
values.
1. Note the values listed in the “Rx Delta Gain Values” field. The values
should be between 0dB and about –3dB.
2. If the values are as expected, go to Ta s k 13
. If they are not, go to
Step 3.
3. Recalibrate the receiver and check the values again.
4. If the values are now correct, go to Step 5. If they are not, go to
Ta sk 1
and check the receiver sensitivity.
5. Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 134. If it has not, go to Tas k 13
.
Task 13 —
AGC Delta Gain
If the RSSI delta gain values are also correct, check the AGC delta gain
values.
1. Note the values listed in the “AGC Delta Gain Values” field. The values
should run gradually from 0dB to about 35dB.
2. If the values are as expected, go to Step 6. If they are not, go to
Step 3.
3. Recalibrate the receiver and check the values again.
4. If the values are now correct, go to Step 5. If they are not, go to
Ta sk 1
and check the receiver sensitivity.
5. Check if the RSSI fault has been removed. If it has, go to “Final
Tasks” on page 134. If it has not, go to Step 6.
6. In this case all the RSSI calibration settings are correct, but there is
still an RSSI fault. Go to Ta s k 1
and check the receiver sensitivity.