Medion MD41527 PS b/d hissing/crackling noise

[tom66]

Re: Medion MD41527 PS b/d hissing/crackling noise

FB: signal which drops as power supply nears the output voltage (usually) only used to keep control loop inside VIPER under regulation. Opto drives it.

Isense: measures current flowing through primary to sense anomalous conditions, such as output short circuit -- if one of these occurs the device will usually latch off for some time (before resetting) or permanently (until power is cycled.)

[notallbad]

Re: Medion MD41527 PS b/d hissing/crackling noise

OK thanks. So doesn't sound like the issue I'm having as it reboots after just a few seconds.

[notallbad]

Re: Medion MD41527 PS b/d hissing/crackling noise

I reflowed various solder joints and the worst of the noise has now gone but the tv is still switching itself off at around 14 mins or so.
So decided to place a large desk fan in front of the PS b/d whilst tv running and it stays on, for over 40 mins, a lot longer than without it.
Remove the desk fan and the tv switched off after 14 mins.

So this is definately an overheating issue for whatever reason, so what is the most likely component to be causing this or how to determine. I know it could still be a solder joint so not totally ruled that out.

Thanks

[akakios]

Re: Medion MD41527 PS b/d hissing/crackling noise

Hi ? i d love to share many experiences about this Delta psu that will help many others having excact the same problem !
I still havent figure what exactly should i replace to stop the noise buzz BUT, i can help pretty good enough! 1st to those who the tv is swithcing after 10 or 15 mins of operation, just add a simle computer fan above the psu (back of the TV) no need to fit it once and for all there ,just to see that your tv will now operate for months without failing (shut Down) . 2nd i ve replaced the factory viper IC8 8pin chip which is 22A with one of 12A AND the sound that was coming from the large blue cap just under the transformer, has reduced its noise by 80%, not a big comfuse as you can now many understand that it has to do something with the current voltage through the Viper IC , tv still works fine without shutting down , no fan for cooland , Vibrate was also coming from mine blue capacitor as well when i was pressing it a bit towards the panel, I dont want what to do next but i think u may share some options with me coz i ve spend many hours and i m in pretty good state right now! Sorry if my English is bad, regards from Greece

[akakios]

Re: Medion MD41527 PS b/d hissing/crackling noise

open the tv again , remove the heta sinks which cover the capacitors, both of them, assemble back cover once again then use a simple fan and check again
mine stays on for days

[mirceamtv]

Re: Medion MD41527 PS b/d hissing/crackling noise

,,There is a heatsink plate that fits over the top of the boards, not shown in the photo".
Suffice it to fit and noise will disappear.