Sony WE475 Service Manual - Page 10

Bias Consumption Current Adjustment, DECK B, Record Bias Adjustment, Record Level Adjustment

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TC-WE475 Bias Consumption Current Adjustment DECK B This adjustment should be performed when replacing the head assy or the bias oscillator transformer (T141, T241). Setting: REC LEVEL knob : standard recording position (See page 11.) Procedure: blank tape CS-413 digital voltmeter set LINE IN no signal R-CH L-CH 1 2 3 TP441 1. Connect the digital voltmeter to test point TP441. 2. Set RV141 (L-CH), RV241 (R-CH) to mechanical center. 3. Press the H button to playback. 4. Adjust T141 (L-CH), T241 (R-CH) so that the digital voltmeter reading becomes minimum. Adjustment Value: Maximum 220 mV Adjustment Location: MAIN board (See page 14.) Record Bias Adjustment DECK B Setting: REC LEVEL knob : standard record position (See page 11.) Procedure: 1. Set to test mode (See page 11.) 2. Insert a tape into deck B, press the REC z button and then press the H button to start recording. 3. Record Mode AF OSC attenuator 10 kΩ blank tape CS-123 set 600 Ω LINE IN 1) 315 Hz 2) 10 kHz 50 mV (-23.8 dBs) 4. Playback Mode recorded portion set level meter 47 kΩ LINE OUT 5. Confirm playback the signal recorded in step 2 become adjustment level as follows. If the selevels do not adjustment level, adjust the RV141 (L-CH) and RV241 (R-CH) to repeat steps 3 and 4. Adjustment level: The palyback output of 10 kHz level difference against 315 Hz reference should be ± 0.5 dB. Adjustment Location: MAIN board (See page 14.) 10 Record Level Adjustment DECK B Setting: REC LEVEL knob : standard record position (See page 11.) Procedure: 1. Set to test mode (See page 11.) 2. Insert a tspe into deck B, press the REC z button and then press the H button to start recording. 3. Record Mode AF OSC attenuator 10 kΩ blank tape CS-123 set 600 Ω LINE IN 315 Hz, 50 mV (-23.8 dBs) 4. Playback Mode recorded portion level meter 47 kΩ set LINE OUT 5. Confirm playback the signal recorded in step 2 become adjustment level as follows. If the selevels do not adjustment level, adjust the RV101 (L-CH) and RV201 (R-CH) to repeat steps 3 and 4. Adjustment Value: LINE OUT level : -23.8 dBs ± 0.5 dB (47.2 to 53.0 mV) Adjustment Location: MAIN board (See page 14.)

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10
TC-WE475
Bias Consumption Current Adjustment
DECK B
This adjustment should be performed when replacing the head assy
or the bias oscillator transformer (T141, T241).
Setting:
REC LEVEL
knob : standard recording position (See page 11.)
Procedure:
1.
Connect the digital voltmeter to test point TP441.
2.
Set RV141 (L-CH), RV241 (R-CH) to mechanical center.
3.
Press the
H
button to playback.
4.
Adjust T141 (L-CH), T241 (R-CH) so that the digital voltmeter
reading becomes minimum.
Adjustment Value:
Maximum 220 mV
Adjustment Location:
MAIN board (See page 14.)
Record Bias Adjustment
DECK B
Setting:
REC LEVEL
knob : standard record position (See page 11.)
Procedure:
1.
Set to test mode (See page 11.)
2.
Insert a tape into deck B, press the
REC
z
button and then
press the
H
button to start recording.
3.
Record Mode
Record Level Adjustment
DECK B
Setting:
REC LEVEL
knob : standard record position (See page 11.)
Procedure:
1.
Set to test mode (See page 11.)
2.
Insert a tspe into deck B, press the
REC
z
button and then
press the
H
button to start recording.
3.
Record Mode
4.
Playback Mode
set
3
2
1
blank tape
CS-413
TP441
L-CH
R-CH
digital
voltmeter
LINE IN
no signal
set
AF OSC
attenuator
10 k
Ω
600
Ω
LINE IN
1) 315 Hz
2) 10 kHz
50 mV (–23.8 dBs)
blank tape
CS-123
4.
Playback Mode
set
recorded
portion
level meter
LINE OUT
47 k
Ω
5.
Confirm playback the signal recorded in step 2 become adjust-
ment level as follows.
If the selevels do not adjustment level, adjust the RV141 (L-CH)
and RV241 (R-CH) to repeat steps 3 and 4.
Adjustment level:
The palyback output of 10 kHz level difference against 315 Hz ref-
erence should be ± 0.5 dB.
Adjustment Location:
MAIN board (See page 14.)
set
AF OSC
attenuator
10 k
Ω
600
Ω
LINE IN
blank tape
CS-123
315 Hz, 50 mV (–23.8 dBs)
set
recorded
portion
level meter
LINE OUT
47 k
Ω
5.
Confirm playback the signal recorded in step 2 become adjust-
ment level as follows.
If the selevels do not adjustment level, adjust the RV101 (L-CH)
and RV201 (R-CH) to repeat steps 3 and 4.
Adjustment Value:
LINE OUT level : –23.8 dBs ± 0.5 dB (47.2 to 53.0 mV)
Adjustment Location:
MAIN board (See page 14.)