Osd Circuit - Zenith XBV323 Series Service Manual

VCR ELECTRICAL TROUBLESHOOTING GUIDE
2. SERVO CIRCUIT
(4) Keys do not work
Keys do not work
Is 5V applied to IC501
Pin79?
YES
Does LED or FLD change
when a function button is
pressed?

4. OSD CIRCUIT

(1) No OSD display.
No OSD or F.OSD display.
Is 5.3V applied to IC501
Pin53?
YES
Does oscillation occur at
IC501 Pins44, 45?
YES
Replace IC501.
(2) I 2 C BUS CHECK
No I 2 C bus communication
Does Power appear at the
Pull up impedence
(R569, R507)?
YES
Replace IC501.
NO
Refer to "SMPS 5.3VA
Trouble Shooting".
NO
Replace the defective
switches.
NO
Refer to "SMPS 5.3VA
Trouble Shooting".
Check or Replace the phe-
NO
ripheral Circurity.(L511,
R518, C596, C595)
NO Refer to "SMPS 5.3VA
Trouble Shooting".
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