HCD-VX880AV - Sony Audio Service Manual (repair manual). Page 7

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• 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 unit ON.

2. Set the tape (AMS-110A).
3. Press the three buttons  

p  ,  ENTER/NEXT  , 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 SYNC  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.

Note: The  

p  button of CD section will become effective and the aging of CD section will stop sometime, if the buttons described in step 3

are not pressed simultaneously. In that case, press  

^  button and operate the CD section.

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)

Symptom

No error

MPEG decoder (IC506)
error

MPEG decoder (IC506)
or
DRAM (IC507) error

H

L

Light

2 time blinking

H

L

H

L

3 time blinking

CN501

1

30

80

D502

SL501

SL502

SL503

CN502

51

IC505

31

(GND)

CT503

VIDEO

Frequency

Adjustment

Check point

(27 MHz)

50

100

81