I have a viewsonic 21 inches, the blue light comes ON then OFF, then OFF, then ON. I can hear a transformer trying to oscillate when turns ON but not sign of life...I replaced a few capacitors, still the same problem. Any idea where I can check?
Computers & Internet - ViewSonic - VA720 17" LCD Flat Panel Monitor
Answers & Comments
I usually replace or the caps in the DC side of the power supply (5v for the logic and the 12~18vdc for backlight inverter circuits).
If you hear squealing sounds then it can be that the inverter oscillator circuits may not be running at the correct frequency due to either bad tunning caps or bad inverter transformers. Please provide model number.
Most common failures in the LCD monitors are bad capacitors (bulging top/seal or leaking) in the power supply, blown fuses, poor solder jopints, failed inverter circuits (blown fuse, shorted transistors, shorted/open transformers), bad lamps (poor solder connections or worn out lamps). You will need to open it up and inspect the inside, see example of failed monitors to get some ideas what to look for: http://s807.photobucket.com/home/budm/allalbums
Post back what you see inside so we can guide you further and it will help out other people in the future also.
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net
Can I get the model number of this Viewsonic? Pictures will help.
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It is either you have transformers with shorted turn or the caps are bad. I need to look for sch.
The screen usually cracked when dropped, that is about it. It could have been coincidented unless it loosen up the solder joints inn the lamp assmblies. Did you also chek the connectors of the lamp assemblies (plug with white and pink wires to see they are seating tightly to the inverter board connectors?)