21HT-15C
21HT-16C
37
NO PICTURE, NO SOUND
CIRCUITS TO BE CHECKED:
Tuner.
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 IC3001 and
at pin6 of IC302/303?
its related circuit.
YES
NO
Check Speaker.
Check IC302/303 and
peripheral circuit.
Summary of Contents for 21HT-15CS
Page 14: ...14 21HT 15C 21HT 16C CHASSIS LAYOUTS Mother unit CRT unit 21HS50F 21HS50C 21HS50C ...
Page 27: ...21HT 15C 21HT 16C 27 ...
Page 32: ...32 21HT 15C 21HT 16C 1 I H G F E D C B A 2 3 4 5 6 7 Page 33 BLOCK DIAGRAMS Mother Unit ...
Page 33: ...21HT 15C 21HT 16C 33 8 9 10 11 12 13 14 I H G F E D C B A Page 32 Mother Unit ...
Page 34: ...34 21HT 15C 21HT 16C CRT Unit 1 I H G F E D C B A 2 3 4 5 6 7 ...
