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B.Video
Repair Flow
check 7701
pin11 HFLB
1.Sympton :
(with white pattern)
no picture
green LED on
check
EHT~25KV
rough check for R, G, B
1. video input= 0.7V
2. 7701video output =2.5V
3. 7705 video output= 35V swing
check 7701
pin5 CLBL
check DC restoration
7707,7727,7747
7706,7726,7746
check 7701 pin24
2V< ABL < 5V
check 7701
pin 6,8,10
input swing
check 7705
pin8,9,11
input swing
Ok
replace 7705
replace IF
cable
No
No
replace 7701
check
VG1 < -190V
Ok
No
check blanking
7421 pin16
check heater
= 6.3V
Ok
check Xray prot.
7651 pin14
No
2.Sympton :
no video (or dim),
only raster with/without retrace line
green LED on
check Vg1
Vg1 = 0V
check cathode
+80V/+180V
Ok
check blanking
7421 pin16
No turn down Vg2
check 7705
pin 1,3, 5
output swing
check
7421 pin16
check
VG2 > 350V
Ok
No
check
7781 pin10
VFLB
3. Sympton :
no OSD or
OSD out of sync.
check 7701
pin 2,3,4 input
check
7701 pin1
check 7781
pin2 VCO
pin3 RP
check 7781
pin5 HFLB
replace 7701
Ok
No
replace 7781
No
check 7781
pin 7,8(IIC)
Ok
No
check
7781 pin12
Ok
Repair Flow Chart
41
109P2 GS3 CM25
9
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