Viking 242-2009-632 - Manual (Page 130)

ALIGNMENT AND TEST PROCEDURES
7-2
March 1999
Part No. 001-2009-600
5. The Synthesizer is programmed for 199 channels
below the Receive Channel.
6. The voltage on U209, pin 6 (TP2) should be
> 2V DC.
7. Record the voltage on J201, pin 13 (TP5) ____.
8. If the voltages recorded in Steps 3 and 6 are not
within
±
0.2V, tune L224 as required to balance the
voltage readings.
9. The Synthesizer is reprogrammed for the Receive
Channel.
7.2.6 FRONT END ADJUSTMENTS
1. Set the signal generator to the Receive Channel at a
level sufficient to produce an output voltage on
J201, pin 7 (TP3) (RSSI Output).
2. Tune L204, L205, L206, L201, L202, L203 and
L204 for a peak voltage on J201, pin 7 (TP3).
Decrease the generator output level to maintain a 2-
3V reading at J201, pin 7.
3. Set the generator to 1000
µ
V with a 1 kHz tone at
±
1.5 kHz deviation (100
µ
V at the Rx antenna with
20 dB pad on the generator).
4. Tune the Quadrature detector coil Z213 for maxi-
mum AC voltage on J201, pin 9 (TP4).
5. Adjust R264 for 387 mV RMS,
±
5 mV RMS, on
J201, pin 9.
6. Adjust R284 for 2V DC
±
0.05V DC on J201, pin 9
(TP4).
7. Measure the distortion on pin J201, pin 9 (TP4)
(analog tuning meter is preferred).
8. Tune C207, L209, L211 and L225 for peak voltage
on J201, pin 7 (TP3). Decrease the generator output
level to maintain 2-3V.
Distortion should be <5% (typically < 3%).
9. Repeat Steps 4, 5 and 6.
7.2.7 AUDIO DISTORTION
1. Plug a 16 ohm resistive load at J101 or J104 on the
MAC (Main Audio Card).
2. Connect a distortion analyzer to the 16 ohm load.
3. Measure the distortion of the receive audio at J101
or J104 on the MAC with the local volume control
set to 2.8V RMS.
4. The reading should be less than 3%
(typically < 1%).
5. Measure receive sensitivity at J101 or J104 on the
MAC.
6. The reading should be < 0.35
µ
V
(typically < 0.25
µ
V).
Optional: Adjust L207, L209, L211, and L225 for
best distortion and recheck sensitivity.
7. The Synthesizer is programmed for 199 channels
above the Receive Channel.
8. The receive sensitivity should be < 0.35
µ
V
(typically < 0.3
µ
V).
Optional: Adjust L204 to balance sensitivity at
±
199 channels if needed.
9. The Synthesizer is programmed for 199 channels
below the Receive Channel.
Optional: Adjust L204 to balance sensitivity at
±
199 channels if needed.
10.The receive sensitivity should < 0.35
µ
V
(typically < 0.3
µ
V).