PCB Trouble shooting

[surfingyetty]

Hello all,
My wire feed motor suddenly stopped working today, so I set about trouble shooting it by following posts about similar problems on here and I have tracked the problem as far as the PCB. I think the problem is most likely with the transistor (is that correct?) but have no idea how to test it. Any advice would be much appreciated!

The information on the transistor is PH BT151 650R m9410 if that's of any help.
I've attached a photo of the whole PCB and of the transistor.

 

[Premiershipman]

Is the fuse supposed to have a black mid section, is there a short that has blown the fuse?

Here is a link to test a mosfet - http://www.4qdtec.com/mostest.html

 

[mike 109444]

Think you will find the "black middle" is the RS brand printed on it (see first pic)

Ref your testing of components. A lot will depend on what sort of test meter you have.
Usually devices like that in this sort or application will 1) blow up! 2) go dead short or 3) go open circuit.

 

[surfingyetty]

Yeah the black on the fuse is writing and I have had the fuse tested and its fine. The wire feed motor works fine when hooked up to a 12V supply and the rest of the welder works fine (the wire will still arc, gas flows etc.) just no wire feed, hence why I think its a PCB fault. I think I need to get a multi-meter tomorrow to test it.

 

[Llama]

Testing the transistor can help I guess, but sometimes you can get funny results without taking the transistor out of the circuit. Keep in mind there are two transistors there

 

[surfingyetty]

I've fixed the problem now, turns out it was a loose connection at the relay and nothing to do with the PCB, oh well!! Thanks for your help!

 

[mike 109444]

Out of interest what machine is it out of?

 

[Wedg1e]

That BT151 is a thyristor, not a transistor, so the techniques for testing a tranny won't help you.

Glad you sorted it anyway...

 

[Wedg1e]

Out of interest what machine is it out of?

Something made around 1994 I'd guess