Lcd, blown caps, works half way.

[munkle]

So I picked up a broken lcd screen for $4, opened it up had 2 leaking caps which I replaced. Turns on now but for one sec and turns off. If I unplug one of the CC it will turn on for about 5 seconds and turns off. If I unplug both CC it will turn on and stay but you can't really use it because there is no backlight. Everything is working on it except the backlight. There were three caps that were the same but only two were leaking, my guess is the third is bad also?

Also not sure if this causes a problem but the caps were 1000uf 10v, I replaced them with 1000uf 35v (only thing I could find remotely close in a store, shipping makes it the same price as a store). I didn't think a higher voltage rating would cause a problem since it just means they are little higher class.

 

[Mohonri]

Using a higher-voltage cap is no problem at all--the voltage rating is a limit of the capacitor, not an electrical characteristic. If those two caps were bad, chances are the third is on its way out as well and should be replaced.

Another possibility is that you have some aging/busted CCFL bulbs in the panel. They're not too expensive to replace, but it's a pain in the neck on most monitors to get them out.

Some pics and model # would be helpful as well. Where did you pick this monitor up?

 

[munkle]

Its an hp 17", i picked up mainly for a project it was at a thrift store. I have fixed two others just by replacing the caps, makes cheap $5-10 monitors. But this one is stubborn. I replaced the third cap, but that didn't fix the backlight, still turns on for a few seconds flickers and turns off and I think I put it into a test mode because now the panel strolls through all the colors and before would just say check vga cable.

I replaced the third cap also, the new ones are the blue ones.

 

[munkle]

Ok so backlight is working now, I switched the order the cc plugs were in. I guess I had them switched up. Now it's stuck in this test mode or what ever it is.

Well I guess I'm just stupid, all I had to do was hook it up a pc and it came out of the test mode.

Another question, the caps I bought are taller and the tops of them touch the metal shielding is that a problem?

 

[PedroDaGr8]

As long as the metal shielding isn't putting pressure on the caps it should be OK. Though be prepared to have to repeat this process in a year or two. Those blue caps are Lelon aka complete garbage. Hopefully they are atleast rated to 105oC where they will have a slightly longer life, otherwise the heat in that backlight inverter will drastically shorten their life.

 

[munkle]

As long as the metal shielding isn't putting pressure on the caps it should be OK. Though be prepared to have to repeat this process in a year or two. Those blue caps are Lelon aka complete garbage. Hopefully they are atleast rated to 105oC where they will have a slightly longer life, otherwise the heat in that backlight inverter will drastically shorten their life.

Yeah, I don't expect them to last that long, but for $9 for a working 17" monitor, I'm not going to complain. There is a little pressure from the shielding on the caps but it wasn't much so I'm not to worried about it. I put some electrical tape on the top metal part just in case (not sure if the top metal part could short out?).