Sharp 21KF-80S - Page 38

38
21KF-80S
NO PICTURE, NO SOUND
Does the noise level increase at
max.
Contrast, Brightness and Sound
Noise increase but .
No signal is received.
No snow noise.
Check the tuner supply voltage
LB must be approx 5V.
BT must be approx. 32V,
and CH preset data check.
Does noise or signal appear
at pin40 of IC801?
Does noise or
signal appear at
pin38 of IC801?
Does noise or
signal appear at
pin23 and 24
of IC801?
Check IC801and
its related
circuit.
Check Q401,
Q402 and its
related
circuit.
Check pin1,2
of SF201, Tuner
and related
circuit.
Check pin37
of IC801and
related
circuit.
Check pin38
of IC801.
Check pin27
of IC801, Tuner
and related
circuit.
Check the Tuner
AGC at TP201.
NO SOUND
Does signal appear
at pin6 of IC302 / 303?
Does signal appear
at pin2 of IC302 / 303?
Check Speaker.
Check IC302 / 303
and peripheral
circuit.
Check IC3001and
its related
circuit.