Aiwa HV-MC90 Service Manual page 43

ELECTRICAL TROUBLESHOOTING -9/13
3. Y/C CIRCUIT
(4) When the Video signal doesn't appear on the screen in REC Mode,
Is the EE signal normal?
Is 5V applied to the IC301
Pins 12, 36, 61, 67, 90, 96?
Does PB Mdoe operate
normally?
Does the RF signal appear
at the IC301 Pin 87?
Does the REC RF signal
appear at the IC301
Pins 87, 88 ?
Check the Drum &
Drum Connector
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Check EE Mode.
Check the line of the 5.3V
Line.(Power Circuit)
Check PB Mode.
Is the REC 'H' signal
(about 4V) applied to the
Q303 Base?
YES
Check REC Luminance
Pass & Color Pass.
Check the circuit of the
IC301 Pins 86, 87, 88, 89.
-43-
Check the System of REC
NO
'H'. (Q303 Base/IC501
Pin 55)
YES
Replace the IC301.
YES