Zenith XBV323 Series, Service Manual

Page: 19 / 140

3-10
4. OSD CIRCUIT
(1) No OSD display.
(2) I 2 C BUS CHECK
Keys do not work
Is 5V applied to IC501
Pin79?
Does LED or FLD change
when a function button is
pressed?
No OSD or F.OSD display.
Is 5.3V applied to IC501
Pin53?
Does oscillation occur at
IC501 Pins44, 45?
Replace IC501.
No I 2 C bus communication
Does Power appear at the
Pull up impedence
(R569, R507)?
Replace IC501.
Refer to “SMPS 5.3VA
Trouble Shooting”.
Replace the defective
switches.
Refer to “SMPS 5.3VA
Trouble Shooting”.
Check or Replace the phe-
ripheral Circurity.(L511,
R518, C596, C595)
Refer to “SMPS 5.3VA
Trouble Shooting”.
YES
YES
YES
YES
NO
NO
NO
NO
NO
2. SERVO CIRCUIT
(4) Keys do not work
VCR ELECTRICAL TROUBLESHOOTING GUIDE