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MODELS: VS-45609 / VS-50609 / VS-55609 / VS-60609 / VS-60719 / VS-70709
Page 28
Purpose:
Measuring
Instrument
Test Point
Measuring
Range
Input Signal
Ext. Trigger
Input Terminal
Symptom:
Purpose:
Measuring
Instrument
Test Point
Measuring
Range
Input Signal
Ext. Trigger
Input Terminal
Symptom:
Oscilloscope
TP14A, TP15A
------
50mV/Div
RF Monaural
300 Hz modulation
RF Input
Set the input signal level to the MCS circuit.
Distorted sound during a stereo broadcast.
1. Supply an RF monaural signal to the Ant A input, 300 Hz at 100% modulation
(25 kHz deviation).
2. Connect the oscilloscope to TP15A (Right Channel). (Junction of
R2K64 and R3A38)
3. Enter the Adjustment Mode and select the Audio Function.
4. Verify that the Audio Function items are set to the data values given the
table below.
5. Adjust Item “1 INP” for 1.55 ±0.06 Vp-p at TP15A.
6. Connect the oscilloscope to TP14A. (Junction of R2K62 and R3A15)
7. Confirm that the left channel output at TP14A is 1.55 ±0.06 Vp-p.
Note:
Adjustment 2 (Stereo Separation) must be performed after this adjustment)
[Audio Circuit]
1. Input Level
Oscilloscope
TP14A, TP15A
------
10mV/Div
RF Stereo
RF Input
[Audio Circuit]
2. Separation
Adjust for optimum stereo separation.
Poor stereo separation
Note:
This adjustment must follow Adjustment 1 (Input Level)
1. Supply a RF Stereo Signal to the Ant. A input.
• Left Channel = 300 Hz modulation
• Right Channel = no modulation signal
2. Connect the oscilloscope to TP15A (right channel). (Junction of
R2K64 and R3A38)
3. Enter the Service Mode and select the Audio Function.
4. Adjust Item “3 WDE” for minimum signal at TP15A.
5. Change the modulation frequency to 3 kHz.
6. Adjust Item “4 SPC” for minimum signal at TP15A.
AUDIO Function
Item Abbrev. Data
1INP 7
2AUT 0
3WDE16
4 SPC 16
15 MZX 1
16 VZX 1
20 ATK 1
SERVICE MODE
Activate …….. MENU-0-1-5-7
Function …...………..AUDIO
Item No. ……….…….VIDEO
Adjust Data ….…….ADJUST
Save Data …. ………ENTER
Exit …………..MENU (twice)
SERVICE MODE
Activate …….. MENU-0-1-5-7
Function …...………..AUDIO
Item No. ……….…….VIDEO
Adjust Data ….…….ADJUST
Save Data …. ………ENTER
Exit …………..MENU (twice)