Samsung Syncmaster 2233rz

[P5k]

Hello everyone.

I'm new to both the forum and electronics, so I could definitely use some help on this one. I've got my hands on a broken Samsung Syncmaster 2233rz 3D monitor, which seems to be having intermittent power issues. You press the power button and it turns on, briefly displays a video signal, then goes black, whereas an LED at the bottom of the screen remains on, so obviously some part of the power supply is still working.

To be honest, this project is very much over my head. I literally only got into electronics a few weeks ago, and this is daunting. Case in point: in my haste to diagnose the monitor, I managed to short out part of the power supply (I know, I'm an idiot  please don't laugh at me). So now I have a second problem to diagnose (although the burnt PCB probably will make that a little easier). Think anyone could give me a hand on how to get started? I am in deep here. Just some recommendations on how not to kill myself through stupidity would probably help...

Pictures below might give you an idea of what I'm dealing with.

[xrunner]

Quick and dirty - unplug it from the wall and re-seat all of the connectors you can find inside. I've fixed a plasma TV once just by doing that. 

[P5k]

Yeah, the capacitors were the first things I looked at - nothing obvious. They all seemed to be in working order from a visual standpoint.

[P5k]

Yeah, the capacitors were the first things I looked at - nothing obvious. They all seemed to be in working order from a visual standpoint.

You can tell they are faulty visually but you can't tell they are good. You have to measure them. Look up ESR. That is commonly the vital aspect that goes. As I understand it the capacitors in a switch-mode power supply are specced for low ESR to minimise heat build up within the capacitor. Heat being the enemy of electrolytic caps. As they fail the ESR rises and so to does the heat build up as a direct consequence. It is a viscious thermal runaway feedback loop. Eventually they spill their guts, but they have failed even before that happens in many cases.

Since you shorted the primary side you have to fix that first.

Yeah, I don't have an ESR meter, but it's definitely on my list.

Are you really sure you want to start with this repair? Aside from the mains power you should wear eye protection. I had a NTC thermistor explode on me. It had a hole blown in the side big enough to poke a match into. The hot bits must have gone somewhere. I could see tiny black specks on a nearby heatsink.

Thankfully I was wearing eye protection at the time. I had stupidly left the PCB resting on the metal frame of the monitor, which created the short. As for this repair ... I guess I didn't realize what I was getting into. I feel very disheartened now.

[wraper]

As of primary problem, likely CCFL inverter transformer (long black rectangle) have one of the secondary windings dead. Should measure about 1 kOhm both, usually one of them  becomes open when faulty.

[P5k]

As of primary problem, likely CCFL inverter transformer (long black rectangle) have one of the secondary windings dead. Should measure about 1 kOhm both, usually one of them  becomes open when faulty.

Thank you. I'll check that once I replace the parts I damaged.

[wraper]

If that area is completely shorted (zero ohms), likely you destroyed diode bridge (black 4 leg part on the heatsink). MOSFET on the another heatsink might be damaged too, however it won't make resistance at that area be measurable as zero.