TC-WE625, TC-WE725, TC-WE825S, TC-WE835S - Sony Audio Service Manual (repair manual). Page 10

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– 10 –
Bias Consumption Current Adjustment
DECK A    DECK B
This adjustment should be performed when replacing the head assy
or the bias oscillator transformer (T81, T91).
Procedure:
1. Connect the digital voltmeter to test point TP81.
2. Set RV81 (L-CH), RV91 (R-CH) to mechanical center.
3. Set to FWD record mode.
4. Adjust T81 (L-CH), T91 (R-CH) so that the digital voltmeter
reading becomes minimum.
Adjustment Value: Maximum 220 mV
Adjustment Location: AUDIO board (See page 11.)
Record Bias Adjustment     DECK A    DECK B
Setting:
REC LEVEL control : standard record position (See page 8.)
Procedure:
1. Record Mode
set
1
2
3
+
blank tape
CS-413
TP81
L-CH
R-CH
digital
voltmeter
LINE IN
no signal
2. Playback Mode
set
AF OSC
attenuator
10 k
600 
LINE IN
1) 315 Hz
2) 10 kHz
38.8 mV (–26 dB)
blank tape
CS-123
Confirm that the 10 kHz playback output is 0 
±
 0.5 dB relative to
the 315 Hz output. If necessary, adjust RV81 (L-CH), RV91 (R-
CH) and repeat the steps given above.
Adjustment Location: AUDIO board (See page 11.)
+
set
recorded
portion
level meter
LINE OUT
47 k
Record Level Adjustment     DECK A    DECK B
Setting:
REC LEVEL control : standard record position (See page 8.)
Procedure:
1. Record Mode
2. Playback Mode
set
AF OSC
attenuator
10 k
600 
LINE IN
blank tape
CS-123
315 Hz, 38.8 mV (–26 dB)
Confirm playback the tape recorded become adjustment level as
follows.
If necessary, adjust Deck A : RV102 (L-CH), RV202 (R-CH) and
Deck B : RV101 (L-CH), RV201 (R-CH) and repeat the steps 1 and
2.
Adjustment Value:
LINE OUT level : –26 
±
 0.5 dB (36.7 to 41.1 mV)
Adjustment Location: MAIN board (See page 11.)
+
set
recorded
portion
level meter
LINE OUT
47 k
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