Zenith ZDX-313, Service Manual

Page: 28 / 136

3-17
3. Y/C CIRCUIT
(2) Hi-Fi Playback
YES
YES
YES
YES
PB mode
No Sound.
Check the Vcc of IC801
(Pins3, 5, 15, 32, 36, 46, 54).
Check the Hi-Fi Selection switch.
(IC801 Pin39) and the Tape quality.
Is the RF Envelope at
IC801 Pin23 over 3Vp-p?
YES
Check IC801 Pin37(Data),
Pin38(Clock)
YES
Do Audio Signals appear at
IC801 Pin80(L-CH), 78(R-CH)?
YES
Do Audio Signals appear at
JK901?
Check Power.
NO
Check IC501 Pin19
(A.H/SW)
NO
NO
Check the parts of µ-COM
(IC501 Pins71, 72)
NO
Check the Connection at
P3D01 Pins7, 9.
NO
Check the Jack(JK901)
NO
Check C801, C851, R801,
R851.
YES