Is it Worth / Possible Pursuing a Fix for a Monitor DVI PCB

E-bay?

If it was at all possible to just buy a replacement god knows I would instead of putting all this time and effort to find out if it is fixable.

A few questions

* The 2 monitors are the same make and model?

* You are using both monitors, at different times, on the same computer and same computer DVI port, right?

* The DVI board is inside the monitor? You're not talking about a DVI card in the computer?

* In other words, the ONLY thing that was changed is the DVI board in the monitor? Does this board plug in? Did you try the DVI board out of the non-functional monitor in the functioning monitor?

I'm not an expert on these matters, but I was given a bad HP 17" LCD monitor. I don't remember the symptoms, but I was pretty sure it wasn't the backlight. I replaced 3 or 4 electrolytic caps and it's been working ever since. It sounds as if you're pretty knowledgeable about these things, so I hope I'm not insulting your intelligence. Bad electolytic caps have been a problem since at least 1999. There is at least one guy making a living on this, his site is www.badcaps.net . If you've absolutely, positively, narrowed it down to this board, I'd replace the electrolytics, since it sounds like you have the ability. If there are a bunch and you don't want to replace them all, you can often tell by leaks and bulges in the cans which ones are most likely bad. (I've also had to replace one cap on a Toshiba CRT TV, and need to replace another one on the same TV.) Oh, you probably know this, but any recent monitor should be able to default to VGA, 640x480 resolution.

Monitor is a Yamakasi Catleap Q270 made by Witech I believe in Korea. Here is a picture of the board in question http://i.imgur.com/Ccntv.jpg. This was before I replaced the capacitor obviously.

2 monitors are exact same make and model with exact same boards. I have tried the non working monitor on different PCs, video cards, DVI cables, and Power brick. I gave it a thorough test in many different environments. DVI board is inside the monitor yes, no computer issues here, just monitor. Only thing that was changed was the board in that picture with the confirmed working board out of my other monitor.

I did not put the bad board into the functioning monitor mostly because when I put the good board in the non functioning monitor it worked exactly like it should, and like it did in the good monitor. I can go back and do this, but I have tested this thing so much I am almost sold that it is something in that picture.

There is no obvious sign of bad caps, burnt markings, or bad soldering that I can see, though again, I am getting a bit out of my field with that so I could easily be missing something.

Thanks for taking the time fellas, I appreciate it!

What is the brand and model number of these monitors? More info might help.

Did you try the non-working DVI board in the other monitor? If it worked briefly, there is a chance it's some borderline condition that might 'go away' when used with the other monitor. Seems illogical, but I've seen stuff like that happen.

Without the PCB schematic it would be very difficult to fix it. Have you tried contacting the manufacturer for any schematics available (some manufacturers don't share this due to intellectual property implications)? You can start by replacing all electrolytic caps, but I have a feeling that the problem lies deeper.

I have worked on a large number monitors - CRT, LCD and LED. Mostly, issues that I have found are either faulty capacitors (electro's mainly) and/or dry joints on the boards. Power boards are by far the most common (including the PSU for the back light and LCD/LED display itself) as this is were the heat is. The first areas that I look at are these. If the caps look OK they still may be faulty. Their quality can be tested and I would then change the starter cap and tank caps and go on to change the lot if necessary. Joints are also worth checking. But once this is done the rest becomes much more difficult and replacing the board is a better choise. It sounds like they were second hand monitors - otherwise you could have the faulty unit repaired under warrentee. I've found replacemnet boards more expencive than second hand units so a full replacement may be cheeper. Hope this helps.

You could use an ESR meter on the caps and you can also try freeze spray. Look for warm components. Something as wierd as comparing the temperatures of components after an hour running or however long the fault takes to appear.

If there is a part number on the PCB try entering that in a search engine.

The display model / serial is worthless, but I have had a fair amount of success getting both schematics and replacement units from the numbers on the circuit board itself.