System/Key Circuit - Philips DVP721VR Service Manual

2. SYSTEM/KEY CIRCUIT

(1) AUTO STOP
Auto Stop
YES
Does the SW25 waveform
appear at the IC501
Pin105?
YES
Do the T-UP Reel Pulses
appear at the IC501 Pin49?
YES
Replace the IC501.
(2) The unstable loading of a Cassette tape
The unstable loading of a
Cassette tape
YES
Is 12V applied to the
PMC01 Pin8?
YES
Does the "H" signal appear
at the IC501 Pin30 during
inserting the CST ?
YES
Does the "L" signal appear
at the IC501 Pin72 during
inserting the CST?
YES
Check the Deck
Mechanism.
Caution :
Auto stop can occur because Grease or Oil is dried up
NO
Check the Drum Motor
signal.
Do T/UP Reel Pulses
NO
appear at the Q514
Base terminal ?
YES
Replace the T/UP Reel
Sensor (RS501).
NO
NO
Check the CST SW and
the peripheral circuitry.
NO
3-7
NO
Does 5.0V appear at the
RS501?
YES
Check the Power Circuit.
Check the Power.
Is 5.0V applied to the
R544 ?
YES
Refer to SMPS 5.3VA
troubleshooting.
Check the IC501
Pins68, 69, 70, 71.
NO
NO