Read Sharp DV-740 (serv.man17) Service Manual online
DV-740H/S(Y,F,S,R)
8
7. SERVICE
No power
TROUBLESHOOTING FLOW CHART
Power troubleshooting
Unplug AC power cord
See flow chart F1 blown
replug it a few seconds later
out
YES
NO
Is the fuse good ?
NO
Replace fuse
YES
Is AT 5V voltage normal ?
NO
Check primary circuit
YES
Is AT -28V voltage normal ?
NO
Check D5,R16
YES
Is AT 3.6V voltage normal ?
NO
Check RG(AMS1085)
R26,R4&circuit
YES
Is JP7 pin10 base pin “H”?
NO
Check MPEG decoder U1 pin
167 AUX5 “H” and line circuit
167 AUX5 “H” and line circuit
YES
Check Q1,2,5,6,7,8,9 circuit ?
In case fuse(F1) blown out
Replace F1 check D001-004,
Check short-circuit
IC1,if poor
replace at the same time
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