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8.2 Trouble Shooting
8.2.1 Main Board
1.NO SCREEN APPEAR
1.NO SCREEN APPEAR
Measured CN201 pin5 = 12 V?
Measured CN201 pin 9/10= 5V?
Measured U202 pin 2= 3.3V?
Yes, all DC level exist
Disconnected the Signal cable( Loose the
Signal cable ),Is the screen show "Cable Not
Connected" ?
No, nothing is show
Connected the Signal cable
again
Led Green
Check the Wire-Harness from CN503
Check Panel-Power Circuit Block
Check U401 Data-output Block
Replace Power board and Check
Inverter control relative circuit
Re-do White balance adjust
Note:1.If replace "MAIN-BOARD" , Please re-do "DDC-content" programmed & "WHITE-Balance".
2. If replace "Power Board" only, Please re-do " WHITE-Balance"
Led Orange
Check Power switch is in Power-on
status , and check if Power switch had
been stuck ?
OK, Keyboard no stuck
OK,Wire tight enough
OK ,Panel Power OK
OK, U203 data OK
Check Correspondent component.
Is there any shortage or cold solder?
Yes .there have OSD show
Connected the Signal cable again,
Check LED status.
Measured RGB (R305, R306,R307 )
H,V Input at U401 pin 37,38 ,was there
have signal ?
Check digital signal from CN301
Measured Crystal X401(14.318MHz)
Replace U401 (MST8111)
OK
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EN7220 Service Manual
Led orange
Check Correspondent
component short/open
( Protection Diode )
OK, input Normal
OK, clock
Led Green
Replace U601
Flash Rom
NG
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