SECTION 5

TROUBLESHOOTING

5.1Feed section

Is 5v or 0V at IC621 pin 40?

YES

NO

Is the wiring for IC621

YES

Is 5V present at IC681

 

 

pin 40 correct?

 

 

pin 6?

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

NO

Check the vicinity of

 

 

 

 

 

IC621.

NO

Check CD8V.

Is 4V present at both sides of the feed motor?

YES

Check the feed motor.

5.2Focus section

5.3Spindle section

NO Is 6V or 2V present at YES IC681 pins 17 and 18?

NO

Check IC681.

When the lens is

 

NO

moving:

 

 

4V

 

 

 

 

 

Does the S-search waveform appear at IC681 pins 13 and 14?

YES

Check the feed motor connection wiring.

Check the circuits in the vicinity of IC681 pins 1 and 2.

YES

Check the pickup and its connections.

Is the disk rotated?

YES

Does the RF signal appear at IC601 pin 19?

YES

Is the RF waveform

at IC601 pin 19 distorted?

YES

Proceed to the Tracking section

5.4Tracking section

NO

NO

NO

Is 4V present between IC681 pins 15 and 16?

YES

Check the spindle motor and its wiring.

Check the circuits in the vicinity of IC601 or the pickup.

NO

Is 4V present at IC621 pin 41?

YES

Check the vicinity of IC681.

NO

Check IC621.

When the disc is rotated at first:

Approx. 1.2V

Is the tracking error signal output at IC601 pin 11?

NO

Check the circuits in the vicinity of IC601 pins 2 to 12.

NO

Check the pickup and its connections.

YES

Check IC621.

(No.MA063)1-29

Page 29
Image 29
JVC KD-LH401 service manual Feed section, Focus section Spindle section, Tracking section