21YF30
TROUBLE SHOOTING TABLETROUBLE SHOOTING TABLE (Continued)
CIRCUITS TO BE CHECKED:
NO RASTER
E Tuner.NO PICTURE, NO SOUND
E PIF.
E Automatic Gain Control.
Check F701.Blown out.E (5V), (32V) Power Source. Does the noise level increase at max.
Contrast, Brightness and Sound controls ?
Replace the fuse.
Noise increases but no signal is
No snow noise.
received.
Check T701 pin (17) voltage
The fuse is blown out again.
(Approx. 310V at 220V AC)
Does noise or signal appear at pin (41)
Check the tuner supply voltage LB must
and (58) of IC801 ?
Check R701and R730.Check IC701, D701 and approx. 5V. BT must be approx. 33V.
C705.And check the CH preset data.
Does noise or
Check Secondary Main+B signal appear at Check IC801 and
(Approx. 130V)pin (63) and (64) related circuit.
of IC801 ?
Check the tuner AGC at
TP201.
Check D751, IC702, D750 Check CRT connector K-Check Q752 for 8V regulator
Check pin (1) of
and IC703.wire and the signal on it.circuit and Q751, Q752 for
SF201, Tuner and Check pin (60) at
305V regulator circuit.IC801 and related
related circuit.
Check pin (59) of circuit.
Check pin(58) of
IC801, Tuner and
IC801.
related circuit.
Check 190V
Check
Bias on
IC801.
CRT board.Checking the
protector circuit.
Does horizontal circuit
oscillate ?CIRCUITS TO BE CHECKED:
E Sound Detector Circuit.NO SOUND
E Sound Switch and Att.
Control.
Check Q601 and Q602.E Audio Output Circuit.
Does signal appear at pins Check TV sound from pin (54)
(10) and (21) of IC3501 ?of IC801.
Does signal appear at pins
(6) and (8) of IC301 ?
Check Speaker.Check IC301 and
peripheral circuit. |
ACEC
