2. Turn the adjustment screw and check output peaks. If the peaks do not match for L-CH and R-CH, turn the adjustment screw so that outputs match within 1dB of peak.
CD SECTION
Note:
L-CH peak Output level
within 1dB within 1dB
1. CD Block is basically designed to operate without adjustment. Therefore, check each item in order given. 2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated. 3. Use an oscilloscope with more than 10M� impedance. 4. Clean the object lens by an applicator with neutral detergent when the signal level is low than specified value with the following checks. S-curve Check Connection:
Screw position
R-CH peak L-CH peak R-CH peak
Screw position
CD board JPO102 (FE1) TP117 (VC)
oscilloscope
3. Mode: Playback
test tape P-4-A100 (10 kHz, �10 dB) L-CH MAIN board CN510 set R-CH pin 3 waveform of oscilloscope
+ �
pin 1 L R pin 2
oscilloscope
Procedure: 1. Connect an oscilloscope to test point JPO102 (FE1) and TP 117(VC) on the CD board. 2. Turn the power on. 3. Put the disc (YEDS-18) in and turned power switch on again and actuate the focus search. (actuate the focus search when disc table is moving in and out) 4. Check the oscilloscope waveform (S-curve) is symmetrical between A and B. And confirm peak to peak level within 2.4 ± 1 Vp-p.
S-curve waveform
symmetry
V
H
in phase 45° good
90° 135° 180° wrong
4. After the adjustments, apply suitable locking compound to the pats adjusted. Adjustment Location: Playback Head (Deck A). Record/Playback/Erase Head (Deck B).
A B
within 2.4 ± 1 Vp-p
Note: � � Try to measure several times to make sure than the ratio of A : B or B : A is more than 10 : 7. Take sweep time as long as possible and light up the brightness to obtain best waveform.
Checking Location: CD board (SIDE B) (See page 24.)
