Disc Loading Is Not Normal; Playback State Cannot Be Set - Kenwood DM-3090 Service Manual

DM-3090

• Disc loading is not normal.

Is disc loaded when it is inserted?
Is the pin 4 of CNP1601 set to L state?
Is change observed on the pin 23 or 24 of IC1601?
Is change observed on the pin 30 or 31 of IC1601?
Check CNP1604 and CN1604
Is ejection performed when the MD taking-out button is
pressed?
Disc retracts soon after completion of disc ejection.
Check CNP1601 and SW1956.

• Playback state cannot be set.

Is it impossible to set both high reflection disc and low
reflection disc to playback state?
Only the high reflection disc cannot be played back.
Is 1.02V±0.3V (high reflection disc) applied to the pin 93 of
IC1401 in the TEST mode where the high reflection disc has
been inserted?
After adjustment check as stated in item "Normal playback".
20
TROUBLE SHOOTING
No
Yes
No
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
No
Yes
Check CNP1601 and SW1956.
No
Check IC1401.
No
Check CNP1604 and IC1601.
No
No
Check as stated in item "TEST mode check".
Yes
No
Only the low reflection disc cannot be played back.
Yes
Is 3.2V±0.3V(record enabied) or 2.06V± 0.3V (record disabled)
applied to the IC1401 pin 93 after the low reflection disc has been
set?
Yes
No
Check SW1951A/B, mechanism switch PWB, and CNP1601.