Servicing Note; Video Section - Sony MCE-K700 Service Manual

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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
(IC501).
The LED (D501) on the VIDEO board indicates their results.
LED (D501) INDICATION
Light
1 time blinking (Repeatedly)
2 time blinking (Repeatedly)
3 time blinking (Repeatedly)
[VIDEO BOARD] — SIDE B —
SECTION 1

SERVICING NOTE

SYMPTOM
No error
External RAM error (IC502)
Video decoder error
(IC507)
Video RAM error (IC508)
— 3 —
HOW TO OPEN THE DISC TRAY WHEN POWER SWITCH
TURNS OFF
Insert a tapeing driver into the aperture of the unit bottom, and turn in
the direction of arrow (to OUT direction).
* To close the disc table, turn the driver in the reverse direction (to IN
direction).
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 repain
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 four times.