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 minutes. The CCFLs were not causing this, they didn't show any pulsing (you can see their white output directly from the side or back when the cover is off)
This was treatable by simply opening a large window with white background on the desktop, i.e. letting heat/light out the front. However, after recapping, this problem doesn't seem to happen, suggesting it was a power-board problem (which is what it sounds like). So far, so good. I'll keep watch for it, but maybe it's cured.
2. I get an intermittent interference pattern, usually only affecting a small part of the screen. It sort of looks like a fine cross-hatching, usually at an angle but just now the cross-hatching was aligned with the screen axes, i.e. vertical & horizontal. You could call it a kind of fuzzy interference pattern I suppose.
Usually if I'm using Word etc I won't even notice this and I only see it if there is some kind of colorful background, eg a movie or picture.
So it's a minor inconvenience really. But I've always thought it was most likely a main board issue.
None of the capacitors on either the power board or the main board looked bad (no bulging or anything else that I could see). But obviously some of those on the power board were bad. The main board has already been recapped under warranty years ago. There are some notorious main-board caps (from memory, C124 and C126) that were among those recapped. But they've had time to go bad I guess, with the amount of heat back there.
Unlike all the other problems, this fuzzy pattern hasn't really gotten worse over time.
I figure that this monitor design really needs a small fan because the power board gets too hot, so my plan is to attach a fan to the back (I'll probably leave the back cover off, it's been like that for years). I tried a PC case fan a few days ago and I'd say it was too powerful, the back of the monitor was stone cold with that running. So I'll reduce the fan voltage or get a smaller fan and see how that goes.
But I'm curious if the "fuzzy interference" symptoms are familiar or suggest anything in particular ...
I figured it bridged to R223, but I wanted you to verify it first. Good job 
As for your other problem it sounds like it might be the mainboard. Do you get fuzziness or some sort of distortion? I checked a picture of that mainboard posted earlier in this thread. I can see what appears to be 2 caps that are slightly bulging on the top left. The big green ones.
As for your other problem it sounds like it might be the mainboard. Do you get fuzziness or some sort of distortion? I checked a picture of that mainboard posted earlier in this thread. I can see what appears to be 2 caps that are slightly bulging on the top left. The big green ones.
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 minutes. The CCFLs were not causing this, they didn't show any pulsing (you can see their white output directly from the side or back when the cover is off)
This was treatable by simply opening a large window with white background on the desktop, i.e. letting heat/light out the front. However, after recapping, this problem doesn't seem to happen, suggesting it was a power-board problem (which is what it sounds like). So far, so good. I'll keep watch for it, but maybe it's cured.
2. I get an intermittent interference pattern, usually only affecting a small part of the screen. It sort of looks like a fine cross-hatching, usually at an angle but just now the cross-hatching was aligned with the screen axes, i.e. vertical & horizontal. You could call it a kind of fuzzy interference pattern I suppose.
Usually if I'm using Word etc I won't even notice this and I only see it if there is some kind of colorful background, eg a movie or picture.
So it's a minor inconvenience really. But I've always thought it was most likely a main board issue.
None of the capacitors on either the power board or the main board looked bad (no bulging or anything else that I could see). But obviously some of those on the power board were bad. The main board has already been recapped under warranty years ago. There are some notorious main-board caps (from memory, C124 and C126) that were among those recapped. But they've had time to go bad I guess, with the amount of heat back there.
Unlike all the other problems, this fuzzy pattern hasn't really gotten worse over time.
I figure that this monitor design really needs a small fan because the power board gets too hot, so my plan is to attach a fan to the back (I'll probably leave the back cover off, it's been like that for years). I tried a PC case fan a few days ago and I'd say it was too powerful, the back of the monitor was stone cold with that running. So I'll reduce the fan voltage or get a smaller fan and see how that goes.
But I'm curious if the "fuzzy interference" symptoms are familiar or suggest anything in particular ...
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