Sanyo DC DA90 – Micro Component System - circuit diagram and adjustments

If the operation of the unit or display is not normal,
1. Disconnect the mains lead.
2. Press the BAND button (main unit) for at least 30 seconds.
3. Connect the mains lead.
4. Operate the unit.

CD PICK-UP MAINTENANCE
About pick-up (Optical lens) Cleaning
Clean a lens with swab of the cotton which moistened it with alcohol, cleaning paper or cleaning disc appointed.
Specified cleaning disc: LC-1 (Part code : 645 026 1961 ..... manufactured by SANYO.)
Show a clean procedure in the following in reference by swab of cotton.
1. Cotton swab is wrapped with cleaning paper.
2. Add the isopropyl alcohol.
3. Gently move the tip of cotton swab just like a draw a whirlpool from inside to outside on the surface of lens.

CD PLAYER ADJUSTMENTS
Confirm the tracking balance
1. Turn on the POWER switch.
2. Connect an Oscilloscope to TP2 (TE) and TP4 (VC).
3. Set the test disc.
4. Press "PLAY" button to turn into the "PLAY" mode.
5. Keep holding "SKIP" button down so as to be "SERCH" mode, then confirm that the oscilloscope waveform is symmetrical on the top and bottom in relation to 0V (VC)

Checking the "eye" pattern

1. Switch "ON" the POWER.

2. Connect an oscilloscope to TP1 (RF) and TP4 (VC).

3. Load the test disc.

4. Press the PLAY button.

5. Check to be sure that the "eye" pattern is at the center of waveform and that the diamond

shape is clearly defined.

6. Press the STOP button.

7. Turn off the POWER switch.

Replacing the head
1. After replacement, demagnetize the heads by using a degausser.
2. Be sure to clean the heads before attempting to make any adjustments.
3. Be sure both channels (1 and 2) are the same level.
(Using a dual-channels oscilloscope).
4. All wiring should be returned to the original position after work is completed

Adjusting head azimuth
1. Load a test tape (VTT-738, etc. :10kHz) for azimuth adjustment.
2. Press the PLAY button.
3. Use a cross-tip screwdriver to turn the screw for normal azimuth adjustment so that the left and right outputs are maximized at the same phase during normal playback.
4. Press the STOP button

Replacing the motor
c. Adjusting motor speed
1. Insert the test tape (MTT-111 or etc. 3,000 Hz).
2. Press the PLAY button.
3. Use a flat-tip screwdriver to turn the SVR to adjust so that the frequency counter becomes 3,000 Hz.
4. Press the STOP button.

Exploded view of CD and Tape mechanism

Schematic-Front

Schematic-CD

Schematic-tuner

Schematic-Amp

Amplifier-PWBA

Output power ......................... 4 W x 2
(at 4 ohms, 10% distortion)
Outputs .................................. SPEAKERS : 4 ohms
PHONES : 8 - 32 ohms
Power requirements............... AC 230V, 50Hz
Power consumption ............... 17 W

Speaker system
Type ....................................... Full range bass reflex
Unit used................................ 8 cm cone type
Maximum power-handling capacity ..... 6 Watts (peak)
Nominal impedance ............... 4 ohms