Philips V50 109B5 Service Manual page 45

rough check for R, G, B
B. Video
1. video input= 0.7V
Repair Flow
2. 7301video output =2.5V
3. 7701 video output > 35V swing
1.Symptom :
(with white pattern)
no picture
green LED on
2.Symptom :
no video (or dim),
only raster with/without retrace line
green LED on
check 7301 pin24
2V< ABL < 5V
check 7301
pin11 HFLB
check check 7301
No
7501 pin16 pin5 CLBL
3. Sympton :
no OSD or
OSD out of sync.
check
Ok
7304 pin12
Repair Flow Chart (Continued)
check
check heater
EHT=26KV
=+6.3V
+/-0.2kV
check blanking
7501 pin16
Ok
check Vg1
Vg1 = 0V
check 7301
Ok pin 6,8,10
input swing
No
replace IF
cable
Ok replace 7301
check 7301
No 7304 pin10
pin 2,3,4 input
Ok
check
7301 pin1
No
replace 7301
check blanking
7501 pin17
Ok
check
Ok
VG1 < -150V
check
VG2 > 350V
No turn down Vg2
check 7701
pin6,7,9
input swing
Ok
replace 7701
check check 7304
pin2 VCO
VFLB pin3 RP
check 7304
pin5 HFLB
No
replace 7304
V50 109B5
Go to cover page
check
R,G,B output
No 30<2725<80
30<2733<80
30<2753<80
Ok
check DC restoration
7722,7732,7752
7721,7731,7751
check cathod
+83V/+190V
check 7701
pin 1,2, 3
output swing
check 7304
Ok
pin 7,8(IIC)
45