Sharp 25WF30, Service Manual, Page: 13 / 47

13
13-1
13-2
25WF30
TROUBLE SHOOTING T
ABLE
Check the voltage at pin (6) of IC1501.
NO VER
TICAL
SCAN
Check IC1501 and related circuits.
Normal
Abnormal
Normal
Check IC800 and its peripheral parts.
Check vertical trigger pulse at pin (26) of IC800.
Check D1576 and R1576.
Abnormal
Does D1200 (Power LED) turn on?
D1200 (Power LED) turn on and of
f.
NO RASTER
Normal
Check CR
T
connector (KY), (H) bias.
Is pin (10) of IC700 in "L" level ?
Abnormal
Check IC850.
Check protecter circuit and its related parts pin (2) of IC1000 vertical pulse.
Check the power circuit consisting of IC700, Q700 IC750 and IC602.
Ye
s
Y
es (RED)
Ye
s
(Bus error)
No
See many often D1200 flashes in red. This indicates which IC to check up.
No
A
Does horizontal circuit momentary oscillate?
Check R1651, IC800 and their peripheral parts.
TROUBLE SHOOTING T
ABLE
(Continued)