Samsuung Syncmaster 244T Power fault.

[eolonano]

Hi guys,
I hope you can shed some light on my problem:

my display went black several weeks ago. Green led was dead too.

So I've replaced all my capacitors with new rubycon caps (or at least I think they are, but I bought them on internet so not so sure).

After that, my monitor turned on immediatly, all perfect.

But now I can hear a very low humming (60 hz, I think) coming from what I think is a metallized film capacitor.

I'm absolutely sure the sound/vibration come from that component.

The capacitor is parallel to the 230v DC, right after the rectifier.

It can be a normal situation? I don't know if that hum was there before the fault, because I really never pay attention to it....

[cpt.charlie]

Re: Samsuung Syncmaster 244T Power fault.

Maybe a bad solder joint? commonly this kind of sound comes from coils/transformers if your new caps have a very different specs, it might cause weird issues (maybe related to the main cap).

[eolonano]

Re: Samsuung Syncmaster 244T Power fault.

I'm checking; I've measured the voltage on that film capacitor and I read 337 DC (????) and I read about 80 volt AC.

I theory in that part of the circuit the voltage has to be DC, because it's right after the rectifier.

It can be the rectifier? I don't really know much about switching power source unit; this AC voltage can come from the 230AC not rectified properly, or it can bounce back from the DC to AC conversion?

[cpt.charlie]

Re: Samsuung Syncmaster 244T Power fault.

Try to locate the schematic first.