Sony HCD-H991AV, Service Manual

Page: 13 / 100

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Record Bias Adjustment (Deck B)
Procedure:
1. Press FUNCTION button to select VIDEO.
2. Mode: record
4. Confirm playback the signal recorded in step 2 become adjustment
level as follows.
If these levels do not adjustment level, adjust the RV341 (L-CH)
and RV441 (R-CH) on the MD board to repeat steps 2 and 3.
Adjustment level: The playback output of 10 kHz level difference
against 315 Hz reference should be
±
0.5 dB.
Adjustment Location: MD board
main board
CN403 Pin
3
(L-CH)
Pin
1
(R-CH)
level meter
recorded
position
set
3. Mode: Playback
Adjustment Location
[MD BOARD] (Conductor Side)
3. Mode: Playback
4. Confirm playback the signal recorded in step 2 become adjustment
level as follows.
If these levels do not adjustment level, adjust the RV301 (L-CH)
and RV351 (R-CH) on the main board to repeat steps 2 and 3.
Adjustment level:
CN403 PB level: 47.2 to 53.0 mV (–24.3 to –23.3 dB)
Adjustment Location: MAIN board
RV441
RV341
RV651 RV652
RV651 (Normal speed)
RV652 (High speed)
Tape Speed
RV311 (L CH), 411 (R CH)
Playback Level (Deck A)
RV341 (L CH), 441 (R CH)
Record Bias
RV301
RV401
RV301 (L CH), RV401 (R CH)
Playback Level (Deck B)
RV311
RV411
Record Level Adjustment (Deck B)
Procedure:
1. Press FUNCTION button to select VIDEO.
2. Mode: record
[MAIN BOARD] (Component Side)
level meter
recorded
portion
set
main board
CN403 Pin
3
(L-CH)
Pin
1
(R-CH)
1
3 IC401
RV301
CN403
RV351
RV301
Record Level (L CH)
RV351
Record Level (R CH)
VIDEO/MD IN
1) 315Hz
2) 10kHz
}
51.2 mV (–23.6 dB)
AF OSC
attenuator
blank tape
CS-123
set
600
Ω
blank tape
CS-123
VIDEO/MD IN
315kHz 51.2 mV (–23.6 dB)
attenuator
600
Ω
set
AF OSC
IC401
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