Philips 202P70/00, Service Manual

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202P7 CRT
31
Repair Flow Chart (Continued)
B. Video
Repair Flow
Rough check for R, G, B
1. Video input=0.7V
2. 7701 Video output=3.4V
3. Video output>35V
1. Symptom:
(with white pattern)
no picture
green LED on
Check hearter
=+6.3V
Check
EHT=25KV
OK
Check
VG1<-150V
NO
Check
R, G, B output
30<2706<80
30<2726<80
30<2746<80
2. Symptom:
no video (or dim)
only raster with/without retrace line
green LED on
Check 7701
Pin 6, 8, 10
input swing
Check 7701
Pin 16, 19, 22
output swing
OK
Replace 7701
NO
Check Vg1
Vg1=-30V
Turn down Vg2
Check cathode
+83V
OK
3. Symptom:
no OSD or
OSD out of Sync.
H.V. Check 7701
Check HUNLOCK
7421 Pin17
OK
Check
VG2>450V