Butters AMT 241 - Bin or Fix?

[QuattroBro]

Hello again all, I've been using my Butters MIG for a few years now and it's been OK, I've mostly been doing light bodywork on cars nothing too taxing. There's features I do like about it especially the decent wire feed.

However, recently the I've been having problems with it, popping, blobbing on the tip and spitting like crazy. Sometimes it will be fine othertimes I can't do a thing with it.

It's not the liner, replaced that, Not dirty wire or lack of gas or me. Torch is fine, earth is good, no obvious loose wires inside either.
So shall I try to fix it or dump it as it's an old machine? And if I do replace it, do I go the inverter route or buy another used large transformer machine?
Thanks in advance.

 

[eddie49]

A solid professional transformer-based machine like a Butters is most probably repairable, and then it will give many more years of good service.
There could be a fault in the wirefeed assembly, or in the high-current DC welding source.

With the gas off and the pressure roller slackened, check that you get consistent torque at all speeds at the wire drive roller, by trying to slow it with a gloved hand. The motor brushes or bearings could be worn, or the gearbox lubrication could be dry or solid.

For each of the 6 voltage steps, check the DC voltage from the torch tip to the workpiece clamp. It should vary from about 15 volts to 27 volts. A different result could indicate a contact problem, or a faulty diode in the rectifier.

Does your welder have capacitors across the output? This would be a bank of a few, or several, electrolytic capacitors, rated at about 5 or 10 thousand microFarads each and wired in parallel.

 

[QuattroBro]

A solid professional transformer-based machine like a Butters is most probably repairable, and then it will give many more years of good service.
There could be a fault in the wirefeed assembly, or in the high-current DC welding source.

With the gas off and the pressure roller slackened, check that you get consistent torque at all speeds at the wire drive roller, by trying to slow it with a gloved hand. The motor brushes or bearings could be worn, or the gearbox lubrication could be dry or solid.

For each of the 6 voltage steps, check the DC voltage from the torch tip to the workpiece clamp. It should vary from about 15 volts to 27 volts. A different result could indicate a contact problem, or a faulty diode in the rectifier.

Does your welder have capacitors across the output? This would be a bank of a few, or several, electrolytic capacitors, rated at about 5 or 10 thousand microFarads each and wired in parallel.

I'd like to fix it ideally of course.

Yes, off hand I think it has caps on the bridge rectifiers I'll grab a photo later.
I suspected wire feed initially, maybe it's that more than a transformer / rectifier problem. It is strange it's intermittent, I'll try the motor feed first.

I've seen mutiple diodes noticeably separated on a similar Butters machine I had years ago.

Thanks for the input.

 

[octo0072000]

check earth lead all the way back to inside machine