Sony HCD-D90AV Service Manual page 15

Record Bias Adjustment (Deck B)
Procedure:
INTRODUCTION
When set to the test mode performed in Tape Speed Adjust-
ment, when the tape is rewound after recording, the "REC memory
mode" which rewinds only the recorded portion and playback is
set.
This "REC memory mode" is convenient for performing this ad-
justment. During recording, the input signal FUNCTION will auto-
matically switch to VIDEO.
1. Press FUNCTION button to select VIDEO. (This step is not
necessary if the above test mode has already been set.)
2. Load a tape into deck B, and press the r REC button.
3. Mode: Record
VIDEO/MD (AUDIO) IN
1) 315Hz
2) 10kHz
AF OSC
600
attenuator
4. Mode: Playback
recorded
position
set
main board
CN403 Pin 3 (L-CH)
5. Confirm playback the signal recorded in step 2 become adjust-
ment level as follows.
If these levels do not adjustment level, adjust the RV341 (L-
CH) and RV441 (R-CH) on the AUDIO board to repeat steps 3
and 4.
Adjustment level: The playback output of 10 kHz level difference
against 315 Hz reference should be ± 1.0 dB.
Adjustment Location: AUDIO board
Adjustment Location
[AUDIO BOARD] (Conductor Side)
RV341(Lch),RV441(Rch)
Record Bias
RV301
RV401
RV441 RV341
RV301(Lch),RV401(Rch)
Playback Level (Deck B)
} 50 mV (–23.8 dB)
blank tape
CS-123
set
level meter
Pin 1 (R-CH)
RV651 (Normal Speed)
RV651 RV652
RV652 (High Speed)
Tape Speed
RV311
RV411
RV311(Lch),RV411(Rch)
Playback Level (Deck A)
Record Level Adjustment (Deck B)
Procedure:
INTRODUCTION
When set to the test mode performed in Tape Speed Adjust-
ment, when the tape is rewound after recording, the "REC memory
mode" which rewinds only the recorded portion and playback is
set.
This "REC memory mode" is convenient for performing this
adjustment. During recording, the input signal FUNCTION will
automatically switch to VIDEO.
1. Press FUNCTION button to select VIDEO. (This step is not
necessary if the above test mode has already been set.)
2. Load a tape into deck B, and press the r REC button.
3. Mode: Record
AF OSC
attenuator
4. Mode: Playback
recorded
position
5. Confirm playback the signal recorded in step 2 become adjust-
ment 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 3
and 4.
Adjustment level:
CN403 playback level: 47.2 to 53.0 mV (–24.3 to –23.3 dB)
Adjustment Location: MAIN board
[MAIN BOARD] (Component Side)
— 15 —
VIDEO/MD (AUDIO) IN
315 Hz 50 mV (–23.8 dB)
blank tape
600 CS-123
set
level meter
set
main board
CN403 Pin 3 (L-CH)
Pin 1 (R-CH)
RV301
Record Level (L CH)
IC401
1 3
CN403
RV351
Record Level
(R CH)