Read Sharp 15JF-25H (serv.man14) Service Manual online
15JF-25H
36
NO PICTURE, NO SOUND
CIRCUITS TO BE CHECKED:
Tuner.
PIF.
PIF.
Does the noise level increase at max.
Automatic Gain Control.
Contrast,Brightness and Sound controls?
5V, 32V Power Source.
Noise increase but no
No snow noise.
signal is received.
Check the tuner supply voltage
Does noise or signal appear
LB and HB must be approx. 5V,
at pin40 of IC801?
BT must be approx. 32V,and
NO
YES
CH preset data check.
Does noise or
Check IC801
signal appear at
and its related
Normal
pin38 of IC801?
circuit.
NO
YES
Check the tuner
Does noise or
AGC at TP201.
signal appear at
Check Q401
pin23 and 24
Q402 and related
Normal
Abnormal
of IC801?
circuit.
NO
YES
Check pin38
Check pin27
Check pin1,2 of
of IC801.
of IC801,Tuner
SF201,Tuner
Check pin37 of
and related circuit.
and related
IC801 and
circuit.
related circuit.
NO SOUND
CIRCUITS TO BE CHECKED:
NO
Audio Output Circuit.
Does signal appear
Check IC801 and
at pin6 of IC303?
its related circuit.
YES
NO
Check Speaker.
Check IC303 and
peripheral circuit.
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