TV power supply question

[whaase]

I have a TV I'm trying to fix (For a while now). I do know a bit about electronics, but not as much as I need/want  The power supply is making a weird buzzing sort of sound and will eventually shut off until it cools down. Attached is a video of what I'm looking at

I think the sound is coming from one of the grey rectangular capacitors that are below the small heat sink. It is marked on top MKP 25 - 150K 450V.

http://vid1202.photobucket.com/albums/bb364/walterhaase/Mobile%20Uploads/tv.mp4

Can anyone direct me what to test or my next step?

Thanks, Walter

[Nickk2057]

what is the model of the TV? and have you also checked the capacitors as well to see if they are bulged?

[whaase]

Its a Dynex 46" LCD from 2011.
Model is DX46L262A12

No capacitors are visibly bulged... I wish they were lol it would be easy then

Walter

[Adam60]

Make, model and a good set of pictures showing the complete power supply board. What are the output voltages on the connectors? Are the electrolytic capacitors bulged on top? Good place to start.

[whaase]

24v was all over then faded away, 12v just slowly dropped and the 5v was solid.

I also attached the service manual I found for it

Walter

[whaase]

Link to service manual

https://www.dropbox.com/s/6w5g1dp0jvh570j/dynex_dx-46l262a12_sm.pdf?dl=0

[Adam60]

Can you attach it another way for those of us who do not use Dropbox?

[whaase]

Hmmm, I will try Google. Hopfully that works

https://drive.google.com/file/d/0B-v7N6Vffcj7NWZ0WDZLbzdYUjQ/view?usp=sharing

[Adam60]

O.K. Little information to go on so far and schematic unclear. Does red light come on/stay on? Does it change color when switched on? Can you check all voltages and provide them in an easy to read format, both before and after switching on (cold) and after it fails. On all connectors?
I atill have suspicions about caps.Do you have cap tester and ESR meter. I am thinking you have high ESR on the caps and this causes your issue. Common on this TV now that we know what it is? Roughly 1.5 years old?

[whaase]

Sorry.  The TV turns on as normal.  That sound in the video starts right away.  It will run for random times.  1 minute one time and 20 the next.  It will shut down and need to sit for awhile before it will turn back on.

I will get all the voltages for you

I don't have a esr meter.  I do have a decent multimeter that checks them.  I know it's not the same.  On a side note,  I have enough caps to redo it all if needed.

I'll update with voltages asap.

Walter

[Adam60]

How old is the TV?
Still suspecting caps. Do you have low ESR caps to replace them. You need good quality Panasonic, Nichicon, Rubycon caps and you will not have problem again for a long time if that is what it is. What brand of caps are in there now? Pearl?

[Grzegorz2121]

This sounds like relay. Maybe supply are having problems with it.