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2.
Horizontal deflection circuit is defective
﹒
circuit R445, C429, FBT, IC401
The horizontal deflection
circuit is defective
Is the voltage on terminal
TP202= 45V?
Is the power supply
circuit normal?
Is the pin1 waveform of
IC401 normal?
Is the pin28 waveform of
IC401 normal?
Is the pin26 waveform of
IC401 normal?
Is the waveform of Q402
"collector" normal?
Is the waveform of Q401
"BASE" normal?
Is the horizontal output
circuit normal?
Is the voltage on terminal
TP201=80V?
Check power supply
circuit
Check H.sync input
Check H-drive circuit
Horizontal out is
defective Q401, FBT
DY is defective
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
0.8Vp-p
64Vp-p
2.4Vp-p
12Vp-p
4.6Vp-p
fH
CRT is defective
No
Check step-up circuit
Q401, Q402, D423, IC401
Check feedback and OSD
Q402, T402
43
ViewSonic
Corporation
Co
nfidential
-
Do
Not
Copy
G90f/B-3
Summary of Contents for G90f/B-3
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