Sharp 21C-FX1C - Troubleshooting Guide: No Raster; Troubleshooting: No Raster; Troubleshooting: No Picture or Sound; Troubleshooting: No Sound

26
21C-FX1(C)/(G) 21C-FX5/FX8
26-1 26-2
TROUBLE SHOOTING TABLE
NO RASTER
Blown out.
Replace the fuse.
Check IC701, D701 and
C707.
The fuse is again blown out.
Does horizontal circuit
oscillate ?
D1001 (Power LED Red)
turns on or turns ON/OFF.
Check T701 pin (7) voltage
(Approx. 310V at 220V AC)
Check F701.
Check Secondary Main+B
(Approx. 120V)
Check CRT connector K1-
K5 bias.
Check IC605, IC751 and
IC801.
Check
C878.
Check
IC801.
Checking the
protector circuit.
Check R615.
D1001 (Power LED red)
turns on and off.
See many often D1001
flashes in red.
This indicates which IC to
check up.
D1001 (Power LED Green)
turns on.
Check D758, IC702, IC753
and D762.
Check R701, R707 and
D709.
LIGHTS UP
TURN OFF
TV PROCESSORE
(IC801)
EEP ROM
(IC1003)
AV SWITCH
(IC401)
SOUND PRPCESSOR
(IC305)
(NICAM/IGR) DECODER
(IC2300)
TUNER
(TU201)
(Bus error)
TROUBLE SHOOTING TABLE (Continued)
NO PICTURE, NO SOUND
Does noise signal appear at
pins (3) and (22) of IC305 ?
NO SOUND
No snow noise.
Does noise or signal appear at pin (40)
of IC801 ?
Noise increases but no signal is
received.
Check the tuner supply voltage LB and
HB must be approx. 5V. BT must be
approx. 32V. 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 IC401 and
related circuit.
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.
Check pin(38) of
IC801.
Does the noise level increase at max.
Contrast, Brightness and Sound controls ?
CIRCUITS TO BE CHECKED:
» Tuner.
» PIF.
» Automatic Gain Control.
» (5V), (32V) Power Source.
CIRCUITS TO BE CHECKED:
» Sound Detector Circuit.
» Sound Switch and Att.
Control.
» Audio Output Circuit.
Does signal appear at pins
(2) and (5) of IC302 ?
Is there audio signal at pins (3)
and (5) of SC2300?
(NICAM/IGR unit socket)
Check TV sound.
Check Speaker.
Does noise or
signal appear at
pin (23) and (24)
of IC801 ?
Check IC302 and
peripheral circuit.
Check IC401.
Check NICAM/
IGR unit, tuner
and its peripheral
circuit.
*NOTE:
NICAM/IGR for model
21C-FX5/8 .