Sony LBT-LX7 Service Manual page 17

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.
(After recording, press the m button without stopping will re-
turn to the position where recording was started.)
1. Press FUNCTION button to select VIDEO 1. (This step is not
necessary if the above test mode has already been set.)
2. Insert a tape into deck B, press the z REC button, and then
press the H button to start recording.
3. Mode: Record
VIDEO 1 (AUDIO) IN
1) 315 Hz
2) 10 kHz
AF OSC
600 Ω
attenuator
4. Mode: Playback
recorded
position
set
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)
16
} 50 mV (–23.8 dB)
blank tape
CS-123
set
level meter
main board
CN301
Pin 1 (R-ch)
Pin 3 (L-ch)
RV311(Lch),RV411(Rch)
Playback Level (Deck A)
RV411
RV311
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 au-
tomatically switch to VIDEO 1.
(After recording, press the m button without stopping will re-
turn to the position where recording was started.)
1. Press FUNCTION button to select VIDEO 1. (This step is not
necessary if the above test mode has already been set.)
2. Insert a tape into deck B, press the z REC button, and then
press the H button to start recording.
3. Mode: Record
VIDEO 1 (AUDIO) IN
315Hz 50 mV (–23.8 dB)
AF OSC
600 Ω
attenuator
4. Mode: Playback
recorded
position
set
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:
CN301 playback level: 47.2 to 53.0 mV (–24.3 to –23.3 dB)
Adjustment Location: MAIN board
[MAIN BOARD] (Conductor Side)
Record Level (Lch)
RV301
CN301
3
1
43
42
29
56
IC301 1
28
14 15
RV351
Record Level (Rch)
blank tape
CS-123
set
level meter
main board
CN301
Pin 1 (R-ch)
Pin 3 (L-ch)