Sony HCD-VR50 Service Manual page 5

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AMS Test Mode
• This mode is used for checking the AMS operations of the tape deck.
JIG
7-819-039-12 Alignment tape, AMS-110A
Procedure:
1. Press the 1/u button to turn the set ON.
2. Set the tape (AMS-110A).
3. Press the three buttons t/CLOCK SET , ENTER , and DISC 3 button simultaneously.
4. "TEST MODE" is displayed on the fluorescent display tube.
5. Press the FUNCTION button and switch the function to the deck with the tape (AMS-110A).
6. Press the CD SYNCHRO button. "AMS CHECK" is displayed on the fluorescent display tube and the tape is rewound.
7. AMS starts in the normal direction. If the AMS count is 2 at shut down, proceed to step 8.
"NG" is displayed at other times, and the deck stops.
8. AMS starts in the opposite direction. If the AMS count is 2 at shut down again, "OK" is displayed.
"NG" is displayed at other times.
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
(IC701).
The results can be checked by D502 of the VIDEO board.
Oscilloscope (Waveform)
Light
TE
L 13942296513
2 time blinking
3 time blinking
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Symptom
H
No error
L
H
MPEG decoder (IC505)
error
L
H
MPEG decoder (IC505)
or
L
DRAM (IC507) error
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2 9
8
[VIDEO BOARD] (SIDE A)
D502
Q Q
3 6 7 1 3 1 5
co
.
– 5 –
9 4 2 8
91
100
1 90
0 5 8 2 9 9 4 2 8
IC505
32 65
33 64
m
9 9
9 9