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: 1. 2. 3. 4. CD Block is basically constructed to operate without adjustment. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated. Use an oscilloscope with more than 10 M� impedance. Clean the object lens by an applicator with neutral detergent when the signal level is low than specified value with the following checks.
L-CH peak Output level R-CH peak
within 1dB within 1dB
5. Check the focus bias check when optical block is replaced.
3. Mode: Playback
test tape HEAD PHONE board P-4-A063 PHONES jack oscilloscope (6.3 kHz, �10 dB) (J500)
Procedure : 1. Connect the oscilloscope to TP (RFACO) and TP (VC) on the CD board. 2. Insert the disc (YEDS-18). (Part No. : 3-702-101-01) 3. Press the
CD u
button.
V set
H
4. Confirm that the oscilloscope waveform is as shown in the figure below. (eye pattern) A good eye pattern means that the diamond shape (�) in the center of the waveform can be clearly distinguished. � RF signal reference waveform (eye pattern)
waveform of oscilloscope
VOLT/DIV: 0.2 V (with the 10: 1 probe in use.) TIME/DIV: 500 ns
in phase 45° good
90° 135° 180° wrong
1.1 0.2 Vp-p
4. After the adjustments, apply suitable locking compound to the pats adjusted. Adjustment Location: Record/Playback/Erase Head
When observing the eye pattern, set the oscilloscope for AC range and raise vertical sensitivity.
Checking Location: � CD BOARD (Conductor Side) �
