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– 11 –
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 microcom-
puter (IC701).
The results can be checked by connecting an oscilloscope to TP709
(LED) of the VIDEO board.
Oscilloscope (Waveform)
Symptom
H
L
Light
H
L
1 time blinking
H
L
3 time blinking
No error
DRAM (IC251) error
H
L
2 time blinking
External SRAM (IC751)
error
MPEG decoder (IC201)
error
oscilloscope
VIDEO board
TP709 (LED)
+
–
[VIDEO BOARD] (SIDE B)
X901
TP709 (LED)
IC751
IC251
SECTION 4
TEST MODE
VIDEO CD COLOR-BARS MODE
On this mode, the data of the color-bars signal as a picture signal
and the 1kHz sine wave signal as a sound signal are output by the
mechanism control microcomputer (IC701) for video CD signal
check. When measurement of the voltage and waveform on the
VIDEO board, perform it in this mode.
For refernce, the color-bars signal can be observed at J9001 (VIDEO
OUT) and the sound signal can be observed at J101 (VIDEO (AU-
DIO) OUT) using an oscilloscope.
1. Connect the lead wire to both ends of the land of SL701 (CAL
2. Turn the power on. Press FUNCTION button to select CD.
3. After 2 or 3 seconds later, connect the lead wire.
4. After measuring, remove the lead wire connected.
NOTE:
The 1 kHz sine wave is not outputted when the CD is played once,
but it is not error.
[VIDEO BOARD] (SIDE B)
SL703 (AFADJ)
IC751
IC251
SL702 (ADJ)
SL701 (CAL BAR)
E-F BALANCE MODE
• Refer to SECTION 6 ELECTRICAL ADJUSTMENTS page 15.
1. Connect the lead wire to both ends of the land of SL702 (ADJ)
and SL703 (AFADJ) of the VIDEO board.
2. Turn the power on. Press FUNCTION button to select CD.
3. Short-circuit the lead wire. (At this time, “DISC” on the fluores-
cent indicator tube will blink (test mode). If it is not blinking,
perform from step 1 again.)
4. Press the
·
button in playback.
5. Every pressing the REPEAT button, the tracking servo and the
sledding servo are turned on or off.
6. When the servo is OFF, the counter on front panel will not be
changed.
7. After measuring, remove the lead wire connected step 1.
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