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CHAPTER 5.
TV
E
Market
21V-FS700S
Service Manual
21V-FS700S
TROUBLE SHOOTING FLOWCHART
[1] TROUBLE SHOOTING FLOWCHART
CIRCUITS TO BE CHECKED:
Tuner.
PIF.
Automatic Gain Control.
(5V), (32V) Power Source.
Check the tuner supply voltage LB must
approx. 5V. BT must be approx. 33V.
And check the CH preset data.
NO RASTER
Check T701 pin (8) voltage
(Approx. 310V at 220V AC)
Check NR701.
Check Secondary Main+B
(Approx. 125V)
Check D751,
Check CRT connector K-
IC702 and IC703
wire and the signal on it.
Check 185V
Bias on
CRT board.
Check IC1001 pin 20.
NO PICTURE, NO SOUND
Does the noise level increase at max.
Contrast, Brightness and Sound controls ?
Noise increases but no signal is
received.
Check the tuner AGC at
JA402.
Check pin (40) of
IC1001, Tuner and
related circuit.
Check F701.
Check
IC1001.
Does horizontal circuit
oscillate ?
Normal
Does noise or signal appear at pin (34)
of IC1001 ?
Does noise or
signal appear at
pin (45) and (46)
of IC1001 ?
Check pin (1) of
SF201, Tuner and
related circuit.
5 – 1
Blown out.
Replace the fuse.
The fuse is blown out again.
Check IC701, D701 and
C705.
Normal
Check D760 for 8V regulator
circuit, IC751 for 3.3V regulator
circuit and IC752, D724, D725
for 5V regulator circuit.
Checking the
protector circuit.
Check Q601,
Q602 and Q803
No snow noise.
Check IC1001 and
related circuit.
Check pin (40) at
IC1001 and related
circuit.
21V-FS700S
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