I have about 30 Viewsonic VP930B's. All of them have no power led or anything. And the switch on the back is turned on. I figure if I can fix one I got them all. I'm an electronics tech but can't do much without a schematic or if components are surface mount. Viewsonic has a power supply for it but it's $350 and out of stock.
-   My VP930b had very similar symptoms. The power LED would blink green non-stop, or it would start working after being left on for a while, or it would just be completely dead. I found the 5V output of the PSU "bouncing" (hence the flashing LED) because those two 1000uF 16V caps were bad. I thought I'd add that, some weeks prior to this problem, a ton (20+) of stuck/lit pixels suddenly showed up, and now they're gone. That could be an early warning sign (I'm guessing the power supply output was getting "noisy").
Note that the caps are high temperature types (105C) and should be replaced with the same. Higher voltage values are OK so long as the replacement will physically fit in place of the original.
-   dekcarc
The power supply was failing due to various bloated capacitors, namely the 1000 uf 16v x2
470 uf 35v x2
220 uf 25v x2
Not all the caps were bad but when 2 or 3 out of 6 are bad, best to replace them all.
The monitors are still under 1yr warranty but VIEWSONIC didn't have any advance replacements, and although they sold me some boxes to ship the bad monitors in, they were the WRONG kind. $50 later in shipping costs they said they didn't have any of the right kind. They have the whole power supply replacement on their online store but says out of stock as well as 3rd party vendors. The electronics stores I went to were low to out of stock on 1000uf caps as well as some of the others. Sorry for the rant.
Yes this is a very common problem on the VP930b. The fault is with the
crappy CapXon capacitors (worst in the industry). As mentioned above,
replace the 220uF@25V and 1000uF@16V capacitors. The other two never go
bad. Make sure you replace the four above even if they look good. I
would recommend using 35V and 25V respectively.
Note, if your monitor serial number starts with Q8H you may have a bad
IC on the main board. Q8 often goes bad a few months after the
capacitors do. If they are warranty they will have to be sent to
Viewsonic or a local authorized service center.
If not warranty, you can solder a wire from the 3 pins on the left side
of the IC to the four pins on the right side. One pin on the left side
is the on/off pin for this IC and should be left alone. This will
bypass the IC allowing +5V to the LCD all the time. However, if the
monitor ever shows scrambled graphics after turning it on then turn it
off using the main power switch in the back and turn it back on, it
should be fine.
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