Re: Newbie with Viewsonic VX2835WM Problem

Oops, I do have another question: the buttons on the front of the VX2835, like other Viewsonic models, are a bit dicey and so I avoid using them where possible to keep them functional as long as possible. So I tend to turn it on/off at the mains. Does this do the power supply any harm compared to using the power button on the front?

Re: Newbie with Viewsonic VX2835WM Problem



Thanks for the links, very helpful. I've rigged up a fan on the back to keep the heat down somewhat, so it doesn't go hurting itself again. Next time I get the chance to take a look, I'll do the following:

(1) check main board regulator voltages
(2) replace any faulty ones
(3) if no faulty regulators, recap the main board

Just now I need to catch up on the work that I need the monitor for, so I'm not sure when I'll do the above. At some point I'll try to get a picture of the interference...

Re: Newbie with Viewsonic VX2835WM Problem



Hmmm, I've just given it a fairly stern test, running a movie with mostly dark scenes for more than an hour, which gets the monitor good and hot because the CCFLs are blazing away but hardly any light is escaping the front. This formerly would cause 2 symptoms:

1. at random intervals the screen would go dark for maybe 20ms. Like a very sudden spike but too short to actually see a black screen, so you would perceive a kind of dark pulse. They would be at erratic intervals sometimes a few seconds apart, sometimes...

Re: Newbie with Viewsonic VX2835WM Problem

Result: perfection!!!!!

Monitor is up and running beautifully!!!

Well, OK, I think it will have some problems when it warms up: this monitor has been living with assorted illnesses for a long time.

BUT, for the first time in years it switched on perfectly. It's had the usual power-supply issues that were getting worse, slow and erratic switching on, various weird stuff and getting worse until it became unusable. So it's been in a corner until I had time to recap it.

I'll describe the...

Re: Newbie with Viewsonic VX2835WM Problem



Thanks for your assistance. When I first lifted the pad (unsoldering the cap), it was left hanging on by the trace, which appeared to go to R223. Then when I soldered the new cap in, the trace broke leaving the pad completely free. The bit where the trace broke off still points to R223, like in the pictures. So that was my theory but it was pretty hard to see (I'm shortsighted, which helps a bit, but still not easy) & I thought it was worthwhile for an expert set of eyes to also have a look, so thanks for that.
...

Re: Newbie with Viewsonic VX2835WM Problem

Hi again,

I forgot part 2 of my question. When I first started recapping the board, all the glue was a bit of a mystery. But now I realize how fragile some of the traces are and so gluing some of the caps might not be a bad idea.

I see epoxy glue mentioned. Is it OK to use silicone on circuit boards? Seems to me it has the right properties but I don't know if it can cause problems.

BTW, very impressed with your war on bad capacitors. I am happy to be joining the good fight

Re: Newbie with Viewsonic VX2835WM Problem

Hi,

I'm also recapping one of these VX2835WM power boards, and I also lifted the pads on some of the caps. I see from this thread that it's a common problem. Mostly I got them soldered OK-ish. But one pad broke completely.

I've marked it on the attached pics (these are pics from earlier in the thread, not my actual board).

It looks like I'm lucky (sorta) because it looks to me like a straightforward problem to fix, but I wanted to ask the experts here before I go putting on a solder bridge...