Servicing Note - Sony MCE-K550 Service Manual

SELF-DIAGNOSIS
This model has the self-diagnosis function for the video and audio
decoder sections.
Immediately after the power on, the self-diagnosis function searches
each operation of IC's around the mechanism control microcomputer
(IC504).
The LED (D502) on the VIDEO board indicates their results.
LED (D101) INDICATION
Light
1 Time blinking (Repeatedly)
2 Time blinking (Repeatedly)
[VIDEO BOARD] — SIDE A —
D502
SL503
SL502
SL501
IC504
IC502
IC503
SECTION 1

SERVICING NOTE

SYMPTOM
No error
Video decoder error
(IC503)
Video RAM error (IC502)
— 3 —
HOW TO OPEN THE DISC TRAY WHEN POWER SWITCH
TURNS OFF
Insert a screwdriver into the aperture of the unit bottom, and turn in
the direction of arrow (to OUT direction).
* To close the disc table, turn the screwdriver in the reverse direction
(to IN direction).
Screwdriver
OUT
IN
Pull out disc table.
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK
OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick-
up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
Carry out the "S curve check" in "CD section adjustment" and check
that the S curve waveform is output three times.