Flyback xfmr cores - where to buy

AFAIK these people do pattern spares LCD backlight inverters:

Good point. In fact, it's unlikely that even the whole transformer is busted -- it's much more likely that the problem lies in the silicon someplace.

Wouldn't it be easier to find the bad component and replace? Or replace the whole power supply with something off the shelf?

Cracked. Plus a bad primary winding. Two windings in parallel actually. One was open.

Try Elna Magnetics

Cheers

First of all you'll need to know which core material is used in the broken transformer... Secondly, if it is a flyback SMPS then the leakage inductance is very important. I doubt you'll be able to wind it by hand.

But like others said: the electronics is most likely the problem. I've repaired a lot of similar equipment but I've never seen transformers fail in power supplies.

Be sure to check whether the LCD monitor is worth your time. New ones are very cheap and if you buy one with LED backlighting you'll save on electricity as well.

s?

Not sure what you need, but LCD TV don't have a raster scan display, so no "flyback". If you're using the term as a generic sub for HV transformer, you might be describing one of the inverter transformers. If so, rewinding these wouldn't make any sense. Google all the numbers that appear on your transformer and locate a used one if need be.

Just FYI, "flyback" is a switchmode power supply topology. Generally the inductor (transformer) has to have an air gap.

It's well suited for wide input voltage range and low to medium power levels.

If you're claiming that a tranformer used in a flyback converter cannot be called a flyback transformer, I don't agree.

Best regards, Spehro Pefhany

Flyback? I guess you could consider the CCFL inverter to have a flyback xformer. I was visualizing a CRT high voltage flyback.

It sure would be nice if you would disclose the LCD monitor maker and model. Also the LCD inverter part number if available.

eBay. Search for "lcd inverter". Google for "LCD inverter" (etc...)

(...)

Gaaah! Careful, Spehro!

Allison gets testy when you call a flyback a transformer. See thread: "Winston is a Vile Autistic Pig" 08/02/2011 in sci.electronics.basics

:)

--Winston

things?

For flyback read switch mode ?

things?

For flyback read switch mode ?

If you like. Flyback converters are a subset of switchmode converters.

A topology that generally requires a gapped core set (which is seldom available off the shelf), unlike some others, so it's actually relevant to the question from the OP.

ne

Cracks make little difference to a gapped core, just glue it back together after winding new coils.

And, if no one has answered your original question, try searching around for Amidon Associates. They sell Fair-Rite ferrite cores, and MicroMetals iron powder cores. They started changing hands a lot at about the same time that I went through a long dry period in circuit design, so I'm not sure just where they are to be found.

They're still around--I just ordered some bead cores from them. Get a copy of their paper catalog--it's pretty retro, but a lot easier to follow than their web site, which consists largely of scanned pages from the catalogue!

Cheers

Phil Hobbs

Or, instead of replacing the 'transformer', just replace the whole power board. If it's an LCD with fluorescent backlight, that HV power board is usually a tiny little thing, costs a few dozen bucks. It's a current-limited AC source, and is more like a ballast than a flyback (DC) switching supply.

This is the main power supply for a Samsung 244T. I did the 'replace all the caps' trick. The 6.3V inverter chip (always on, provides control power for everything else) was bad. I replaced that and got about 1.5 Vdc out of the secondary (after the diode). Unwound the transformer and found the core (it appears to be ungapped) to be cracked and 1/2 of the primary winding to be open. I could find all the broken pieces, glue it back together and rewind the old core, but I'd rather start fresh.

There is a transformer with core and windings spec'd in the inverter app notes, so I can probably find the right part.

I've Googled for a new power supply board, but all I get are pages from link farmers. So

Check Ebay. There are a lot of new, used & rebuilt circuit boards availible.

I don't know if Igor still updates this, but at one time it was useful.