Service manual

2000 SERIES RECEIVER DECODER MODULE (RDM)
3-16
March 2000
Part No. 001-3139-502
4. Tune Z213 for 2V ±0.05V on TP4.
5. Tune R264 for 387 mV RMS, ±5 mV RMS, on TP4.
6. Repeat Steps 4 and 5.
7. Measure the distortion on TP4.
8. Tune L207, L209, L211 and L225 for minimum dis-
tortion <5%, (typically <3%).
9. Repeat Step 8 then Steps 4, 5 and 6.
3.11.6 FRONT END ADJUSTMENTS (REV. 6)
REVISION 6 BOARDS
1. Set the signal generator to the Receive Channel at a
level sufficient to produce an output voltage on
J201, pin 7 (RSSI Output).
2. Tune L204, L205, L206, L201, L202, L203 and
L204 for a peak voltage on J201, pin 7. Decrease the
generator output level to maintain a 2-3V reading at
J201, pin 7.
3. Set the generator for 1000 µV into the receiver with
a 1 kHz tone at ±3 kHz deviation (100 µV at the
receive antenna with 20 dB pad at the generator).
4. Adjust the Quad Detector Coil Z213 for 2V DC on
U202, pin 9.
5. Adjust R264 for 387 mV RMS on J201, pin 9 (TP4).
6. Adjust R282 for 2V DC ±0.05V on J201, pin 9
(TP4).
7. Measure the distortion on TP4.
8. Tune L207, L209, L211, L225, C373 and C375 for
minimum distortion <5%, (typically <3%).
9. Repeat Step 8 then Steps 4, 5 and 6.
3.11.7 AUDIO DISTORTION
1. Plug a 16 ohm load at J204 on the RDM.
2. Connect a distortion analyzer to the 16 ohm load.
3. Measure the distortion of the receive audio at J204
on the RDM with the local volume control set to
2.8V RMS.
4. The reading should be < 3% (typically <1%).
5. Measure receive sensitivity at J204 on the RDM.
6. The reading should be < 0.35 µV (typ. 0.25 µV).
7. The software programs the synthesizer for
3 MHz above the Receive Channel.
8. Receive sensitivity should be less than 0.35 µV
(typically less than 0.30 µV).
9. The software programs the synthesizer for
3 MHz below the Receive Channel.
10.Receive sensitivity should be less than 0.35 µV
(typically less than 0.30 µV).
11.The software programs the synthesizer for the
Receive Channel.
12.Set the generator to the Receive Channel and adjust
the level for 15 dB SINAD.
13.Adjust R261 for 0.8V DC ±0.02V DC at TP3
(RSSI).
14.Repeat Steps 4 and 5.
15.Measure the distortion on TP4.
16.On Revision 5 or earlier boards: Tune L207,
L209, L211 and L225 for minimum distortion
<5%, (typically <3%).
On Revision 6 boards: Tune L207, L209, L211,
L225, C373 and C375 for minimum distortion
<5%, (typically <3%).
17.Repeat Step 8 then Steps 4, 5 and 6.