What is wrong with my computer monitor?

[Jooder492]

I have an old pc monitor that i decided to get out and fix. it is an old LCD monitor that i had laying around that decided to stop working a long time ago. I tested the fuse and it was still good. I tested a couple diodes and it turns out that only about half of them were good. Does this mean that my monitor is fried and cant be fixed? They all failed open and the fuse is still good btw.


if i let is sit out for about 3-4 months then plug it in, the screen does turn on for about half a second. idk what letting it sit out would do unless its to do with the compasitors loosing charge.

 

[Birdman Adam]

That might just be the case. However, theres a chance some capacitors or transistors may have gone bad and short-circuited, stopping the power supply from doing its job. (That could be why your diodes died too). I just fixed a lcd monitor that had popped one of its caps. I guess Dell didn't think about putting a 1000uF cap against a very hot heatsink... I would wait for some others to post as well - they have more experience than me.

 

[Jooder492]

funny you should say that... i was looking at my heatsink and i also got a few 1000uF caps that look kinda bloated compared to other ones... they got a very small bit of buildup on the top but it dosent look like they poped... they might have gone bad. how would you test them?

 

[Torben]

funny you should say that... i was looking at my heatsink and i also got a few 1000uF caps that look kinda bloated compared to other ones... they got a very small bit of buildup on the top but it dosent look like they poped... they might have gone bad. how would you test them?

You'd take them out and test them with the capacitance range on a multimeter and, even better, test the ESR if you have the tester for that (which I'm going to guess you don't; I don't see them around a lot).

However, if they're bloated and leaking electrolyte, I wouldn't bother checking them--I'd just replace them as they're probably either shot or at least one foot in the grave. In fact I'd probably replace all the the electrolytics just on principle (although a true repair guy like Nigel, tcmtech, etc would be able to give you much better advice or tell you if I'm hallucinating again).


Regards,

Torben

 

[Nigel Goodwin]

funny you should say that... i was looking at my heatsink and i also got a few 1000uF caps that look kinda bloated compared to other ones... they got a very small bit of buildup on the top but it dosent look like they poped... they might have gone bad. how would you test them?

As Torben says, they are duff - replace them - it's by FAR the most common fault these days.