Repairing Switched mode power supply type welder

It's a common enough type with suitable substitutes also made by most major power semi vendors.

Maybe if you said which country you live in I could help advise a source.

Graham

snipped-for-privacy@volcanomail.com wrote in news:1168308527.848268.122730 @s34g2000cwa.googlegroups.com:

Digi-Key says: MOSFET N-CH 500V 20A TO-247 made by STMicroelectronics

but they don't stock it.

The NTE cross-reference at

says you can replace it with an NTE2970, but that doesn't seem to be stocked either.

Anyone?

Make sure you check the rest of them as well, if one is blown, chances are more are bad.

These are pretty much generic parts. Not sure what the B means but most 20N50s should do the job I'd reckon.

Graham

Farnell don't have 20n50s but do have 20n60s.

Don't mix up the IGBTs and mosfets. Also check what IR and STM have.

Graham

On 8 Jan 2007 18:08:47 -0800, snipped-for-privacy@volcanomail.com put finger to keyboard and composed:

Try RS Components, part number 248-4242, ST part number STW20NB50.

Datasheet:

Otherwise Farnell appear to have the STW20NK50Z.

- Franc Zabkar

Hello,

Thanks very much for all the replys. I will order some FETS and see how I get on.

There is a service manual for the welder available at

Cheers, Andy

Try