Electrical Adjustment - Akai AC-220 Service Manual

IV. ELECTRICAL ADJUSTMENT
4-1. CASSETTE DECK ELECTRICAL ADJUSTMENT
PRECAUTIONS:
Before adjustment, clean and demagnetize the heads and tape guides.
ADJUSTMENT STEP:
1. TEST TAPEffEST CONDTION
2. MODE
3. CHECK POINT/ADJUSTMENT PART
4. REMARK(•---> Test point) AND RESULT (*-3>-Adjustment part)
2 TAPE
II
NORMAL(x)1 SPEED
1. 3,000Hz Test Tape
2. play
3. Adjust VR508
4. Connect a frequency counter to
play L&R output test point TP3
(GND) and TP1 (LCH), TP2
(RCH) 3000Hz ± 30Hz
,----
1
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1
TAPE II
HIGH(x)2
SPEED
1. 3,000Hz Test Tape
2. Tape II, play; Tape I, REC and
HIGH DUBBING
3. Adjust VR509
4.
Connect a frequency counter to
play L&R output test point TP3
(GND) and TP1 (LCH), TP2
(RCH) 6000Hz ± 60Hz
--L-------,--7---7
, - - - - - - - - - . - - - 1 - - - - - - 1 - - - -
CDffUNER/TAPE
PCB (TOPVIEW)
VR509
VR508
(GND)
TP6
(RCH) VR501
9~ VR502 (LCH)
@9
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L ____ _
CN106
r-0
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3 BIAS OSC
FREQUENCY
1. No input signal, normal recording
test tape.
2. REC
3. Adjust T503
4. • Connect a frequency counter
between CN106 GND & ERASE
*
96KHz+2/-1 KHz
-f
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13
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c3
6
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TP1
(RCH)
TP2
[3
(LCH)
TP3
(GND)
EQ/AMP P.C BOARD
(BOTTOM VIEW)
4 NORMAL POSITION BIAS
1. Connect AC Voltmeter between TP6
(GNO) and TP5(Lch), TP7(Rch) Rec
Adjust VR502(Lch), VR501(Rch) to
10mV (6.5mV AC-220)
2. AUX INPUT 1 KHz and 1 0KHz
LEVEL -20dB (Ref: TAPE 0dB)
3.
REC and PB
4.
Confirm the signal level
of 1KHz
and
1
0KHz is equal or within +0/-3dB
If not good, repeat 1-3 steps