snap-on 130 turbo troubleshoot

[scooby9858]

hi all i have got a non working snap-on 130 mig and after reading through the forum i have tried various things to to diagnose the problem.to start with only the power and the fan came on.and no transformer hum or voltage on the out side.i then connected a piece of wire in the two pins of the plug i pulled from the board going to the contactor and i now hear the humming noise and i get the following voltage on the dc multimeter.both leads coming from the transformer to the plates 29v , contractor 40v, tip of gun 29v and goes down to zero when i press the trigger.but the feed motor does not turn?.also is it usual for the transformer to be rusted.has anyone any idea so i can get it working thanks for any help.

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[mike 109444]

Not sure why you are getting " and i get the following voltage on the dc multimeter.both leads coming from the transformer to the plates 29v" As that should be AC not DC there or are you setting your meter for that test to AC? Any way as the feed motor gets its power from the same source as the welding current then could be that the feed motor is dragging down the voltage due to a fault maybe. Try as you have done before jumper ect then metering between the earth clamp and the wire tip with meter set to DC. Then do same but with the feed motor wires disconnected (mark them so you know which way round!) If the voltage does not drop now then you have something pulling it down from the wire feed side. Could be the motor, or the control on the pcb. Try feeding the motor from a separate 12v DC source such as a batt charger. If it runs ok then suspect the pcb. Would need pic to advise.
I think the attached pic is of your type welder. The yellow line is the feed motor (13) getting it's power and the red line is the welding current , so you can see motor pinching it's feed from weld current.

 

[scooby9858]

thanks mike i rechecked with the multimeter again and major problems its not 29v its 2.9
and upon further investigation ive discovered the bottom left of the four wires that enter the big transformer winding is broken right as it enters the winding dont think that can be repaired.ive tried to put up a photo.thanks again.

 

[mike 109444]

It MIGHT be possible to fix. If it has broken due to fatigue rather than being fried!
Your pic is not clear enough. If you can post better pics then might be able to advise.
It might be possible to tease out enough of the wire to crimp a sleeve to rejoin to ori wire
using something like 1st item on this page http://www.toolstation.com/shop/Electrical/Crimp+Terminals/d190/sd2712