Sharp 14BM2G Service Manual - Page 16

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TROUBLE SHOOTING TABLE
CIRCUITS TO BE CHECKED:
NO PICTURE, NO SOUND
Tuner.
PIF.
Automatic Gain Control.
(5V), (33V) Power Source.
Does the noise level increase at max.
Contrast, Brightness and Sound controls ?
Noise increases but no signal is
received.
Check the tuner supply voltage LB must
be approx. 5V. BT must be approx. 33V
and CH preset data check.
Normal
Check the tuner AGC
at TP201.
Normal
Abnormal
Check pin (27) of
Check pin (38) of
IC801, Tuner and
IC801.
related circuit.
CIRCUITS TO BE CHECKED:
» Sound system pins (28) and
(44) of IC801.
» Sound Detector Circuit.
» Sound Switch and Att.
Does signal appear at pin
Control.
(44) of IC801 ?
» Audio Output Circuit.
YES
(Signal)
Does signal appear at pins
(6) and (8) of IC301 ?
YES
Check P301 connector of
IC301 and peripheral circuit.
(Continued)
No snow noise.
Does signal appear at pin (40) of
IC801 ?
NO
Does noise or
Check IC801 and
signal appear at
its related circuit.
pin (38) of IC801 ?
NO
YES
Check Q205 and
its related circuit.
Does noise or signal
appear at pins (23)
and (24) of IC801.
NO
YES
Check pin (1) of
Check pin (37) of
SF201, Tuner and
IC801 and related
related circuit.
circuit.
NO SOUND
NO
Does signal appear at pin (28)
of IC801?
YES
NO
Check C356 and
Check IC801.
peripheral circuit.
Check Q301, pins (4) and (6)
of IC801 and peripheral
circuit.
16-1
TROUBLE SHOOTING TABLE
HORIZONTAL SYNCHRONIZATION
CIRCUIT TO BE CHECKED:
Sync. Separator Circuit.
YES
NO
Normal
Check pins (21) and (22) of
IC801.
NEITHER VERTICAL NOR
Check pins (16), (17) and
(34) of IC801.
DEFECTIVE VERTICAL AMP.
AND VERTICAL LINEARITY
Readjust Vertical Size.
(Bus Data)
Vertical Linearity and Size
are abnormal.
Check R503, R504, R506,
R513, C517 and D501.
NO VERTICAL SCAN
Check IC501 Bias pins (3)
and (6).
Abnormal
Check C503, C507 and
power supply circuit.
16-2
(Continued)