Help needed to identify a transformer on LCD TV PSU

Thread Starter

trustno1

Joined Sep 18, 2015
5
Transformer indicated in the red box below is generating mechanical buzzing noise which is quite annoying. I decided to replace it but i cant identify the part. Can you help me identify it? Also, i would like to know if there is any other way to get rid of the buzzing besides replacing it.

19a0d41e-2a97-4ef4-affe-212baac98d57 (1).jpg
 

AlbertHall

Joined Jun 4, 2014
12,345
The cause of the buzzing is unlikely to be the transformer itself even if that is where the noise is coming from.
It is more likely to be that large electrolytic capacitor is either low value or high ESR, or some other problem causing instability in the power supply.
 

ian field

Joined Oct 27, 2012
6,536
Transformer indicated in the red box below is generating mechanical buzzing noise which is quite annoying. I decided to replace it but i cant identify the part. Can you help me identify it? Also, i would like to know if there is any other way to get rid of the buzzing besides replacing it.

View attachment 135984
It looks like a Vestel PSU, they own one of the largest collections of familiar trusted brand names - they trade badges like stocks & shares.

You're much more likely to find one in another scrap TV than on any service replacement parts catalogue.

AFAIK: that's the PFC inductor - if you're desperate, there's a really naughty bodge; The PFC front end is essentially a flyback boost converter. If you remove the PFC MOSFET(s) and link out the inductor, the main switcher gets fed a lower input voltage. It will draw sharp current blips from the mains, so don't boast about it to the utility company. Also; the main switcher has to run more mark and less space to get the job done.

A few online suppliers offer the whole board - AFAICR: just over £20 in UK money.
 
Last edited:

ian field

Joined Oct 27, 2012
6,536
You can remove the transformer/choke and soak it in varnish for 30 mins, let it dry and replace it,..
I'd check the ferrites were actually loose before doing anything that might compromise its flame retardant rating.

PFC inductors can and do self cremate - SMPSU chopper transformers usually damage other components; bang stops play.
 
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