Sony MHC-DX50 Service Manual page 18

HCD-DX50/RG80
DECK B
REC Bias Adjustment
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
MD/VIDEO (AUDIO) IN (J101)

1) 315 Hz

2) 10 kHz

AF OSC
600 Ω
attenuator
5. Mode: Playback
recorded
portion
set
CN301 (Pin 3 : L-CH)
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
DECK B
REC Level Adjustment
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.
16
50 mV (–23.8 dB)
blank tape
CN-123
set
level meter
+
–
(Pin 1 : R-CH)
4. Mode: Record
MD/VIDEO (AUDIO) IN (J101)
315 Hz, 50 mV (–23.8 dB)
AF OSC
600 Ω
attenuator
5. Mode: Playback
recorded
portion
set
CN301 (Pin 3 : L-CH)
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
[MAIN BOARD] (Component Side)
T11
RV11
PB LEVEL (L)
(B)
REC LEVEL (R)
(B)
REC BIAS (L)
[LEAF SW BOARD] (Component Side)
TAPE SPEED
(NORMAL) (HIGH)
RV1002
RV1001
blank tape
CS-123
set
level meter
+
–
(Pin 1 : R-CH)
REC LEVEL (L)
PB LEVEL (L)
(B)
(A)
CN304
CN301
3 1
RV301
CN302
RV302
RV303
CN303
RV351
RV304
RV354
REC BIAS (R)
(B)
(B)
CN1001