Sharp 14BM2, Service Manual

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16
16-1 16-2
14BM2, 14BM2S/G 20BM2, 20BM2S/G 21BM2, 21BM2S/G
TROUBLE SHOOTING TABLE
(Continued)
TROUBLE SHOOTING TABLE
(Continued)
NEITHER VERTICAL NOR
HORIZONTAL SYNCHRONIZATION
CIRCUIT TO BE CHECKED:
Sync. Separator Circuit.
NO VERTICAL SCAN
Check R503, R504, R506,
R513, C517 and D501.
DEFECTIVE VERTICAL AMP.
AND VERTICAL LINEARITY
Readjust Vertical Size.
(Bus Data)
Check pins (16), (17) and
(34) of IC801.
Check IC501 Bias pins (3)
and (6).
Normal Abnormal
Vertical Linearity and Size
are abnormal.
Check pins (21) and (22) of
IC801. Check C503, C507 and
power supply circuit.
NO PICTURE, NO SOUND
No snow noise.
Does signal appear at pin (40) of
IC801 ?
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.
Check the tuner AGC
at TP201.
Does noise or
signal appear at
pin (38) of IC801 ? Check IC801 and
its related circuit.
Check Q205 and
its related circuit.
Does noise or signal
appear at pins (23)
and (24) of IC801.
Check pin (1) of
SF201, Tuner and
related circuit. Check pin (37) of
IC801 and related
circuit.
Check pin (27) of
IC801, Tuner and
related circuit.
Does the noise level increase at max.
Contrast, Brightness and Sound controls ?
CIRCUITS TO BE CHECKED:
Tuner.
PIF.
Automatic Gain Control.
(5V), (33V) Power Source.
Abnormal Normal
Normal
YES
YES
YES
NO
NO
NO
Check pin (38) of
IC801.
Does signal appear at pin
(44) of IC801 ?
NO SOUND
Check IC801.
Check C356 and
peripheral circuit.
CIRCUITS TO BE CHECKED:
»
Sound system pins (28) and
(44) of IC801.
»
Sound Detector Circuit.
»
Sound Switch and Att.
Control.
»
Audio Output Circuit.
Does signal appear at pins
(6) and (8) of IC301 ?
Check P301 connector of
IC301 and peripheral circuit. Check Q301, pins (4) and (6)
of IC801 and peripheral
circuit.
Does signal appear at pin (28)
of IC801?
YES YES
(Signal)
YES
NO
NO
NO