No wire feed under a load

[mark501w]

I have a cheepy Power Mig 130t sold by Harbour Freight it's about 15yrs old. I think it's a Italian job. I run flux core wire in it, it has intermittant feed under a load. I've done the basic approaches to feeding problems. In trouble shooting I noticed that the wire feed has plenty of torque, but will stop if I ground the tip to my table. I hate to throw the little machine out. Got any ideas?

 

[mark501w]

I weld for 20-30 seconds then the motor stops,I wait afew seconds& it starts again & welds for a few seconds ect. All the while pressing the trigger ?What would cause power to be intermittant to the motor? Or what would reduce the voltage while using welding current?

 

[mike 109444]

As you say the welder is quite basic I would expect that it gets it voltage for the motor from the voltage that feeds the welding, much as some of the basic SIP and Clarke welders do. It could be that you have one of the diodes in the rectifier (an ally plate or two usually) going down OR a poor connection that is dropping the voltage to the motor when the weld is under load. With the power disconnected If you follow the power feed cables from the feed motor back then one should go to the ally plate of the rectifier. Check by removing and cleaning this and any other connections including your work ground clamp lead.
And welcome BTW

 

[mike 109444]

If you look at the top left of the rectifier plates you will see the red wires that connect there. One of these is the power feed to the motor (will/may go via pcb relay) This is from a Clarke 130en
Looking at the second pic (130en diagram) If yo follow the red arrows you can see how it "pinches/taps off" some of the weld power

 

[mark501w]

Thanx for your time cleaning & brightening didn't hurt. Runs a little longer before it starts stuttering. I think it may be a heat related issue.

 

[the snooper]

View attachment 84450 Thanx for your time cleaning & brightening didn't hurt. Runs a little longer before it starts stuttering. I think it may be a heat related issue.

Look at the negative side, we see quite a few problems there when crimps are used, if you find a crimp look for discolouration from heat, remove the crimp and remake the joint

 

[mark501w]

What do I use to tie the joint together?

 

[mark501w]

Anyway thanks for looking no hot spots, I suspect it's electronic. I'll put it on Craig's list for a pair of Tbones.

 

[mike 109444]

Pair of Tbones ???

 

[mark501w]

Steaks

 

[mike 109444]

It could be a fault with the thermal cut-out (the white box mounted on transformer) It should "normally" act as a short but when hot form prolonged welding it will go open circuit cutting power from welding voltage (and as a result the feed motor) You could try bypassing it as a "test" by linking the two wires together. IF IT WORKS OK THEN REPLACE as it is a safety device.

 

[mark501w]

Weld voltage is ok it's the motor voltage that is intermittant.

 

[the snooper]

in that case remove the circuit board and look for dry joints

 

[mark501w]

Looked at the board when I cleaned plugs pulled it looks cherry.

 

[the snooper]

Looked at the board when I cleaned plugs pulled it looks cherry.

a test, weld until it cuts out then using something insulated pull the trigger and start tapping the circuit board and motor if it springs to life you have found where the fault is

 

[mark501w]

It's intermittant ,If I keep the trigger down starts on it's own.

 

[the snooper]

It's intermittant ,If I keep the trigger down starts on it's own.

tapping may exaggerate the fault giving you some clues

 

[mark501w]

I think what ever splits the power off the board to supply the motor heats & is letting the signal threw intermittantly.

 

[mark501w]

Thanks for the help Carlos has got it now & I'am heading for Stater Bros. for a couple of T bones.