Question about ViewSonic VG800 18" LCD Monitor
I have repaired several Viewsonic VX800 monitors. The symptoms include a power light that flickers or flashed on and off or a screen that flashes on briefly or stays off. The problem is bad electrolytic capacitors on the power supply board. These bad capacitors do not look bad and do not swell but they do develop a high ESR (Equivalent Series Resistance). You need a ESR meter to check them. But if you have these problems, you should assume the capacitors are bad and just go ahead and replace them.
First you must open the monitor and gain access to the power supply board.
1. Remove the stand: It is held with 6 screws on the back. Also on the back are 2 black screws that must also be removed.
2. Remove the button bar from the front, bottom: It is pried off. This will expose the 2 screws holding the front plastic bezel.
3. Remove the silver plastic bezel from the front: First remove the 2 screws holding it, then you can pry the rest off. This will expose the 2 screws holding the screen to the plastic back.
4. Remove the screen and electronics from the plastic back: Remove the 2 screws holding it. The 2 speakers are glued to the plastic case. Cut the glue with a knife. The screen and electronics and speakers should lift out of the plastic back.
5. Remove the metal cover to expose the electronics: There are 2 screws holding the VGA connector and 2 screws holding the DMI connector. There are 9 screws holding the cover. These must all be removed. There is a black plastic sheet glued to the lower edge of the cover. It must be lifted. The cover should now come off.
6. Replace the bad capacitors. The power supply and signal processor are on the same board. It is marked VG800-2. The bad capacitors are surfaced mounted 100UF 25V. The bad capacitors are CM16, CM17, CM2 and CM165. The two most critical are CM16 and CM17, but they all read high ESR, so I just replace them all as long as I have them exposed.
Reassemble in reverse order.
Posted on Apr 17, 2013
If you can solder and are acquainted with electronic parts (or if you have a friend who does), go to this website:
I spent just an hour doing this and it worked. Hope this helps.
Posted on Mar 09, 2009
Its a problem with bad caps on the power board, problem is that it would cost you more to fix it then to buy another monitor cause your looking at the cost of either capacitors or a whole board if it can't be repaired component level and labor.
My suggestion is to get a new monitor. The repair cost would exceed the cost of a new monitor.
Posted on Feb 10, 2009
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