56FW-53H (serv.man56). Fault finding flow charts for the DA100 (50Hz) chassis - Sharp TV Technical Bulletin (repair manual). Page 2

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Neon
illuminated
NICAM or OPC
LED's illuminated
Plug or Internal fuse has failed
 Check Bridge Rectifier,Q701, Q702,
Q703 and D712
Plug or Internal fuse has failed
 Check Bridge Rectifier,Q701, Q702,
Q703 and D712
No
Short Circuit
Check HT
(D720 Cathode)
No
Yes
Power supply is working correctly
check data communication
(see LED's Fault code table)
Power supply is working correctly
check data communication
(see LED's Fault code table)
No
Short circuit on a supply other
than the main HT
Short circuit on a supply other
than the main HT
line Drive Missing
go to chart 2
line Drive Missing
go to chart 2
140v
Between 20 And 40 Volts
Zero
Press CH+ button
on main PWB
Remove R623
No
Yes
CTV not faulty
standby mode
CTV not faulty
standby mode
Protection circuit operating
Check IC1001 pin 95
(5v = Normal\zero= standby)
Protection circuit operating
Check IC1001 pin 95
(5v = Normal\zero= standby)
Power supply in standby mode
check IC702
Power supply in standby mode
check IC702
Power Supply Starts
No Change
Power Supply Starts
For A Few Seconds Only
Chart 1 -  No 140v rail
Before switching on ensure that the aerial is not connected
IC702
pin15 = 0v
HT has increased
replace IC705 and check
associated components
HT has increased
replace IC705 and check
associated components
Power Supply not working
Replace R713 and R714
check D712, Q702 and Q703
Power Supply not working
Replace R713 and R714
check D712, Q702 and Q703
Yes
Note:
An avalanche diode has been
added across C720
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DA50 Chassis
Fl
Sharp Electronics (UK) Ltd
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