HCD-GX8000, HCD-RG77 - Sony Audio Service Manual (repair manual). Page 20

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20
HCD-GX8000/RG77
4. Mode:  Record
5. Mode:  Playback
6. Confirm the play back signal recorded in step 3 becomes
adjustable level as follows.
If these levels are not adjustable level, adjust the RV301 (L-
CH) and RV351 (R-CH) on the MAIN board to repeat steps 4
and 5.
Adjustable level:
CN301 PB level:  47.2 to 53.0 mV (–24.3 to –23.3 dB)
Adjustment Location:  MAIN board
REC  BIAS  ADJUSTMENT   DECK B
Procedure:
In the MC test mode, the “REC memory mode” is convenient for
this adjustment. In the “REC memory mode” , when the REC starts
the input signal FUNCTION is switched to VIDEO automatically.
When the REC stops, the tape returns near to the recording start
position.
1. Press
MD (VIDEO)
button to select VIDEO. (This step is not
necessary if the above test mode has already been set)
2. Insert a tape into deck B.
3. After press 
[REC PAUSE/START]
 button, press 
[REC PAUSE/
START]
 button, then recording start.
4. Mode:  Record
5. Mode:  Playback
6. Confirm the playback signal recorded in step 3 becomes
adjustable level as follows.
If these levels are not adjustable level, adjust the RV304 (L-
CH) and RV354 (R-CH) on the MAIN  board to repeat steps 4
and 5.
Adjustable level: Playback output of 315 Hz to playback output
of 10 kHz:  
±
1.0 dB
Adjustment Location:  MAIN board
REC  LEVEL  ADJUSTMENT   DECK B
Procedure:
In the MC test mode, the “REC memory mode” is convenient for
this adjustment. In the “REC memory mode” , when the REC starts
the input signal FUNCTION is switched to VIDEO automatically.
When the REC stops, the tape returns near to the recording start
position.
1. Press
MD (VIDEO)
button to select VIDEO. (This step is not
necessary if the above test mode has already been set)
2. Insert a tape into deck B.
3. After press 
[REC PAUSE/START]
 button, press 
[REC PAUSE/
START]
 button, then recording start.
attenuator
set
MAIN board
MD/VIDEO (AUDIO) IN (J750)
1) 315 Hz
2) 10 kHz
50 mV (–23.8 dB)
600 
blank tape
CN-123
AF OSC
+
set
recorded
portion
MAIN board
CN301 Pin 
2
 (GND)
MAIN board
CN301
Pin 
1
 (L-CH)
Pin 
3
 (R-CH)
level meter
set
MAIN board
MD/VIDEO (AUDIO) IN (J750) 
315 Hz, 50 mV (–23.8 dB)
blank tape
CS-123
600 
attenuator
AF OSC
+
set
recorded
portion
MAIN board
CN301 Pin 
2
 (GND)
MAIN board
CN301
Pin 
1
 (L-CH)
Pin 
3
 (R-CH)
level meter
TAPE SPEED
ADJUSTMENT
RV1002
RV1001
(NORMAL)  (HIGH)
CN1001
– SW BOARD (Component Side) –
– MAIN BOARD (Component Side) –
REC LEVEL
ADJUSTMENT
REC BIAS ADJUSTMENT
CN301
3
1
(R-CH)
(R-CH)
(L-CH)
(L-CH)
RV301
RV351
RV304
RV354
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