System/Key Circuit - Zenith XBV323 Series Service Manual

VCR ELECTRICAL TROUBLESHOOTING GUIDE

2. SYSTEM/KEY CIRCUIT

(1) AUTO STOP
Auto Stop
Does the SW30 waveform
appear at IC501 Pin18?
YES
Do the T-UP Reel Pulses
appear at IC501 Pin80?
YES
Replace the IC501.
Note :
Auto stop can occur because Grease or Oil has dried up
(2) The unstable loading of a Cassette tape
The unstable loading of a
Cassette tape
Is 12V applied to PMC01
Pin8?
YES
Does the "H" signal appear
at IC501 Pin60 during
inserting the CST ?
YES
Does the "L" signal appear
at IC501 Pin19 during
inserting the CST?
YES
Check the Deck
Mechanism.
NO
Check the Drum Motor
signal.
Do T/UP Reel Pulses
NO
appear at the point
between R556 and R536?
YES
Replace the T/UP Reel
Sensor (RS501).
NO
NO
Check the CST SW and
the peripheral circuitry.
NO
3-7
NO
Does 5V appear at the
RS501?
YES
Check the Q160 Power
Circuit.
Refer to "SMPS DRUM
12 Volt Trouble Shooting".
Is 5V applied to R531 ?
YES
Refer to SMPS 5.3VA
troubleshooting.
Check IC501
Pins22, 23, 24, 25.
NO
NO