Capacitor Voltage Question

[NightrainSrt4]

So, I have been doing a bunch of research on the lcd my brother gave me that turns on but the backlight turns off within a second. The picture still shows, but you can't see it without a backlight, and the light when it does light up for that time looks perfect. From what I read this model has an issue with bulging caps, and replacing those has fixed this exact issue with several people.

Sure enough I open it up and look at the exact capacitors that those with the same issue described as bulging, mine were too. No visible leaks or anything but bulging.

Anyway, to the question:

I need a 1000uf 16V cap, and a 470uf 16V cap. Radioshack has the correct uf but 35V is the closest ones. From what I read it is perfectly okay to go with a higher voltage, just it might be too large for the space. Is it true that you can use a higher voltage capacitor without issue, as long as it is the same uf rating?

[Oneslowz28]

yes the voltage is just how much voltage the cap can safely handle. it would be much much cheaper to order from digikey, electronics gold mine. Raidoshacks caps are cheap and could go bad in a short time. Digigeys stuff is high quality

The caps go bad for 2 reasons. The manufacture buys the cheapest they can find and they are over volted. I suspect yours are a combo of both. Moving to a 32v cap might solve this prob for ever.

$0.60 each. They are 35v but will work fine.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=493-1085-ND

[mtekk]

Do note that Digikey has a minimum order amount (IIRC it's $20), so make sure you can fulfill that with stuff you are getting otherwise they'll charge you it for $5.00 worth of stuff.

[NightrainSrt4]

Thank you very much for the help and info. I will probably go through the website you linked me and get some higher quality caps, but would going with just 2$ worth of radioshack caps be okay, at least temporarily? That way I could grab what I need and at least see if that solves the issue. If that does work I could then grab a whole bunch down the line and redo all the caps on the board with high quality stuff?

[Oneslowz28]

the caps from RS will most likely work for the life span of your monitor. I believe that the caps they used it in were a a high tolerance (+/- 50%) elchepo caps that most manufactures use. the RS ones will more than likely be +/- 20% caps and will fair better than the cheap ones the manufacture used.

I forgot about Digikeys minimum order policy.

[NightrainSrt4]

Cool. I really hope that the couple bulging caps are all that is affecting it. Everything else on the board looks fine. A $2 fix would be great, and be a free lcd essentially. No point in paying $70 bucks or whatnot for an inverter board.

If it doesn't work, I should look for a school projector, as the image is on the screen, just needs a backlight source. Hmmm...if it doesn't work, the backlights work fine. Maybe I will wire them up to a CCFL inverter board and just run that into a pc. Have the matrix run though the regular power, and the light off the pc. That would probably work too.

[x88x]

Or, you could try an LED conversion, that would be cool.
(Awesome about the monitor, btw).

[NightrainSrt4]

All I can say is FRICKEN YAYA, well actually there were some expletives, but hell yes!!!!!

+rep to you all.

I ran to radioshack, picked up 2 1000uf 35v caps and 2 470uf 35v caps (only needed 2, but extras in case), and a better iron as my battery one sucks monkey balls for anything important. Got back home and realized my sucker was missing. Went ahead and went carefully anyway.

Swapped out the two sightly bulging caps, plugged it in and fired it up and BAMN perfect picture. Stayed on perfect. I got too excited so I haven't stress tested it or anything, just ran over here to tell the good news.

:banana::banana::banana::banana::banana:

[Oneslowz28]

congrats!!!

[NightrainSrt4]

Thanks. Now I feel retarded though. In my excitement I threw it all back together, and fricken clipped the power cable under one of the screws. Well, put the back panel on, and didn't realize that one of the wires was pinched between the panel and the screw terminal.

Crap. Power is all intermittent now because of it. Now have to strip the casing off and fix any of the wires that are messed.

[Oneslowz28]

DOH! Facepalm

[NightrainSrt4]

Ya seriously, lmfao. I fixed it though. Stripped the insulation of the wires, the ground wire wrapped around the wires. Only the power wire was broken (partially), so I cut that all the way and put a little extension in between and soldered the connections. Then because the ground was like an insulating wrapper I had to cut that originally to get to the other wires, so I cut a new ground wire and soldered that up.

Put it all back together and this time taped the wires down in a spot they wouldn't get clipped. Powered up and seems to be working great once again. Woot!

Face palm indeed.

[x88x]

Awesome. Do you have a third video output on your desktop that you're gonna hook it up to or will it be used with a different system? Also, what's the model (or at least size/res)?

[NightrainSrt4]

It will most likely be used with one of the other systems. My 280 only has 2 outputs and those are being used, and unless I get a pci nvidia card I can't get any triple monitor action.

The monitor is a 17" Envision EN-7100si, I believe. 1280x1024.

[x88x]

Nice, so not a big one, but a very usable size.

So I'm assuming you have no onboard video? That's one of the really nice things about my new MBB; since it has the GeForce 9400 NB/onboard GPU, I have two extra outputs :D I never thought I would use the third monitor as much as I do, but hey, ain't that always the case :twisted: Now it feels so cramped when I go back to "just" two 22" panels :P

[NightrainSrt4]

Ya, no onboard video with my motherboard. I've got a pci 9250se in one of my servers that really doesn't need it as it has onboard and almost never gets output to a screen as I usually just rdp to it. But you can't run ati and nvidia drivers on vista from what I've heard. Apparently win7 has the function to run separate vid drivers, so maybe when I go to 7 i'll go tri monitor.