fault with mig- lack of current, not burning in correctly-help please

[rcminiman]

Hi guys,
Im a DIY mini restorer, and went to use my wee Nu Tool NW130 mig last night, but it refused to burn in at all. It melts the wire into pidgeon droppings, but thats all, and thats on all settings. The power varies as the settings are changed, but they are proportionally low.
I have contacted Nu Tool by phone just now, but they didnt seem to have a clue or care as to the fault.:full
Are there any knowledgeable folks out there that can assist me with my fault please?
I am an experienced Mechatronic Engineer by trade, so know the insides reasonably well. I havent gone round it with a DMM yet to check voltages/diodes etc. I got mighty cheesed off with it and gave up hope last night! Will return to it tonight fully armed with hopefully more info from you guys.

Cheers.

 

[weldequip]

Check torch & earth lead connections first, what's the condition of the earth clamp?
Also, internally, check connections from the main transformer to the rear of the earth lead connection + any other connections that may be loose
weldequip

 

[rcminiman]

The connections are great as far as I could tell. I cleaned up the earth clamp. It was fearsome dirty before!
I should have some more info tomorrow, and hopefully an answer.

 

[rcminiman]

Well, after a quick diagnosis, the fault was traced to a blown diode in the rectifier. The welder was putting out ac volts, so this naturally means the rectifier is at fault.
I have found a couple of large diodes to try out tonight, so fingers crossed I can fix the exhaust on the missus car afterwards. How exciting!!
Cheers