Wire Feed Problem

[TDVT]

Hi, I have a MM 130xp I bought 9 or 10 years ago.

No problems until today. I went to tack some parts, the feed ran v-e-r-y slowly then just stopped. Dug out the manual, checked the fuse on the PCB which was OK. Everything else was working as it should (arc, etc.) Seemed it was the drive motor.

I checked around anyway & the rheostat measures OK but I'm getting 5v AC max at the motor terminals ? (for a 24v AC rated motor)

Then I read a post on the Hobart page about testing the drive motor with 12v DC.

Tried it & the motor works.

Anyone have any ideas? Bad circuit-board?

Thanks, TD

[weld_13]

what type of wire r u usin? so ur motor works with good voltage to the motor? what about tension on the spool? not to tight not to loose.

[Black Wolf]

I think you mis-read his post young feller. I don't believe his issues are wire related. It's more of a pull the trigger and the wire feed motor doesn't work anymore kind of thing. I'd like to offer some help, but my experience is with Lincoln Electric wire feeders, and I can't think of anything generic to check that hasn't already been done.

Best of luck,
Later,

[Sundown]

There two wires at the gun that connect to the switch that control the current when the trigger is pulled. Sometimes one of both of the spade connectors will work loose or even become disconnected. If you apply current to the motor and it works then check the connection at the gun.

[Black Wolf]

That's a good point George.

I was going to post that too, but when I re-read his post - specifically about the drive motor turning very slowly then stopping, I thought it to be a control board issue vs. a gun connection issue. He did state too, that he had arc voltage, and gas flow, just no drive motor.

My experience with the gun connection problem that you brought up is that condition is first intermittant-starts off by moving gun the wrong way and losing contact to lastly complete - gas solenoid does not engage, no arc voltage, drive motor will not turn.

I have never seen this loss of contact to cause the drive motor to slow down, only cycle solenoid on/off and stop drive motor completely. Usually faulty rheostat or control board affects drive motor speed. Unfortunately, I do not have any Miller specific diagnostic information to offer.

Later,

[TDVT]

Thanks for the replies!

Basically, the motor doesn't operate at all (connected to the welder) so it's not wire/tension related. Actually, I checked those first & then pulled the spool, etc..... nothing.

The motor won't run from any internal power. I got it to run when I applied 12vDC from a battery, with the motor disconnected from the unit. The 5v AC I get at the motor connectors (from the PCB?) occurs when I pull the gun trigger but goes back to zero when I release it, but I'll check those connections in the gun just to make sure.

Thanks, TD

[Sundown]

That's a good point George.

I was going to post that too, but when I re-read his post - specifically about the drive motor turning very slowly then stopping, I thought it to be a control board issue vs. a gun connection issue. He did state too, that he had arc voltage, and gas flow, just no drive motor.

My experience with the gun connection problem that you brought up is that condition is first intermittant-starts off by moving gun the wrong way and losing contact to lastly complete - gas solenoid does not engage, no arc voltage, drive motor will not turn.

I have never seen this loss of contact to cause the drive motor to slow down, only cycle solenoid on/off and stop drive motor completely. Usually faulty rheostat or control board affects drive motor speed. Unfortunately, I do not have any Miller specific diagnostic information to offer.

Later,

You are probably right, but on a gun that old it won't hurt to check the connections, can't do much else on Sunday anyway.

[tsalagi]

when was the last time you changed the liner? if it was recent, did you maybe put a kinck in it?

[Iron man]

This may not help but I had an old century welder that done that it was the wire speed selector switch.

[Goodhand]

I'll just throw something out in hopes it might help. In the past few months, I've experienced a couple of electrical malfunctions that were remedied by pulling spade connectors and re-attaching. In the first case it was my microwave oven. One day it just quit, so I checked the HV cap and diode after pulling the connectors. These two components checked ok, and when I hooked 'em back up, the oven worked. A week later, it quit, again. Went through the same procedure a few times, before I hit on the connectors. I pulled 'em off the posts, re-crimped, and hooked back up. Microwave has been working better than new ever since. I blame corrosion, due to electrolysis, between the wire and the connector.

Couple days ago, my garage door opener started to work intermittently, then would only work if I, continually, depressed the push-button to power the motor. I employed my newly-found fix technique... first I unplugged the power cord, then pulled and re-attached the spade connectors one by one. Plugged cord back in and it's been working great ever since.

If you try the above method to trouble-shoot and fix, and it is not successful, you might take a peak at any capacitors that might be on the power supply board. Caps often leak or otherwise go bad after about 10 years in use.