There are 2 boards/parts involved with this problem
a) The power supply board:
The main problem are 4 bad/defective capacitors and shorted legs due to bleeding of soldering lead (brownish color).
1. 22uf 400v
2. 47uf 50v
3. 1uf 100v
4. 22uf 35v
You can find them near the PWM IC controller (U601). Replaced all these capacitors regardless they look good. I pulled them out off the board and tested them with my Blue ESR and capacitor tester and found 3 were defective.
Next, you need at least 97% Isoprophyl alcohol and toothbrush to clean the soldering paste. Due to overheating on the primary section / HOT section the soldering leads tend to produce brownish paste which is causing the component parts to SHORT. Concentrate at the back of the board, especially at the U102 (16-pin IC) and Q202 transistor by scrubbing them carefully. I used magnifier to make sure the legs are clean and shiny. Clean the rest of the back and some part on top of the board. Let it dry for 2 hours at least. I did 2 times this cleaning to complete the process.
b) The Main Board
The main board has 2 bad capacitors at C124 and C126. I replaced them and cleaned also the board with alcohol.
That's it. Good Luck.
Roan Mac
Computer Tech
Chapel Hill, NC
In this model the capactors hardly ever dome or vent. Usually you will see the top of the labeling on the capacitor has shrunk a little from it's normal size. If the monitor still has any kind of power (which it does from your comment) you or someone you know can replace those capacitors on the output side of the supply. If you're lucky this will solve your problem. If not, you can always try replacing the four brown electrolytic capacitors on the inverter board (the long board on the left when viewing the monitor from the back). There is a chance this could be caused by the inverter board or even a bad backlight, however I would bet it's the power board. If you don't want to replace the capacitors or replacing them didn't solve the problem, contact Viewsonic at viewsonic.com and get the price of a new power board. They are pretty easy to replace.
Nice article, i replaced all the Capacitors on the power board it powers up fine but windows does not reconize it as plug and play and will only allow it low resolution. I will try changing the two capacitors on the video board, as you suggested, mine are swelled at the top. And yes there is yellow brown stain on the power board i will take your suggestion and try to clean it up. Thanks
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It is not resetting problem, more likely the power supply had failed, or the backlight inverter circuits, or bad lamps. You need to open it up and inspect the capacitors in the power supply section first, look for cap with bulging top/seal first, post back what you see inside so we can guide you further, see example of failed Viewsonic mnoitors due to bad caps, lamps, transformers, etc: http://s807.photobucket.com/home/budm/allalbums
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