Hobart 120 HELP

[meteorman]

I've got an older (early 90s) Hobart Handler 120 with gas shielding.
It's not working correctly. I'm having two problems that may or may not be related.

1. the wire feed doesn't work at all when the speed is below 7. works poorly at 7, seems fine at 8-10.

2. when welding at wire speed 8-10, the arc cuts in and out- making it really difficult to weld

what I've done.
replaced the rheostat.
replaced the diodes and capacitors on the board.
posted it on cList.
used foul language

I checked with Hobart, they are telling me to check connections. I've checked everything I can see and don't see any bad connections.
the tech wants me to check the trigger handle I don't see how this could be the problem, since it works fine at speeds 8-10 without welding. and not at all under 7.


Could it be the motor for the wirefeed? how do I diagnose that?

 

[icebox]

I don't know who you spoke with at hobart tech . But Keith is the best guy there ask to talk to him . What I have found is it is hard to figure it out if it ain't there where they can test it.
icebox

 

[Old Iron]

Does the trigger wires plug into the machine or fastened direct ?
If they plug in make sure the spade connectors are not loose fitting.

 

[Dirtyrat]

Hmmm, I'll ask, since I didn't see it in your list, did you check the feed rollers (making sure you have the right roller for the diameter wire you are using) and setting the tension on the feed roller assembly?

I wonder if you have a short in the leads for the weld gun...

Just starting simple here, not sure if that will help.

 

[Sunnybeach]

I am not sure how the spool attaches but make sure it can move freely and is not "overly tight" causing the feed rollers to slip or stall.

Another thought, is the tip the correct size and clean so that the wire can move through the entire system easily?

 

[meteorman]

wire feed spool

these are good things to check. The issue I'm having isn't the spool, or the wire feed rolls. (i think)
I am having trouble with the feed, but when it's not feeding, it just clicks and doesn't try to feed.
The spool is loose and working fine.
I'll check all the connections again, I've looked at them as best I can, but I'll get in there again and look for a loose connection.
The issue I'm having is that when I'm not welding, the wire feeds fine.
But when I'm welding it stops and starts again.

I replaced the rheostat with an original Hobart part, the replacement I used before was a Miller (owned by same company, I understand) but the rating was different. The one I put in is rated at the correct wattage (like original)

This seems to help me to be able to feed the wire at lower speed. It is now feeding down to 3/4 ok. But when I weld, it's still stopping and starting- although it seems a bit better.
Maybe I'm just really bad at this. I can seem to do much better with an ARC welder. but mig is supposed to be so much easier- so I'm hoping there's something wrong with the machine.

 

[Torchie]

Not an expert by anymeans but here are some basic things to check.
Feed tension. Too much is as bad as too little.
Kinks in the snake. Make sure the the feed tube is not kinked thus impeding the feed.
Correct tip for the wire size that you are using.
Check your feed rate. To get that bacon sizzle that everyone talks about I find that I have to increase my feed rate beyond specified guidlines.

And last but not least. Make sure that you are pulling the trigger all the way.
It sounds stupid but with the shape that my hands are in and wearing the gloves sometimes I get intermitent feed because I think tht the trigger is all the way in and it isn't.

Keep trying and don't get too frustrated.
Hope some of this helps you.
Torchie.

 

[hotrodbill]

Have you tried replacing the tube liner? Inside the feed tube there is a liner that looks like a tightly wound spring.

They DO NOT last forever.
They get kinked, especially at the ends, they get full of slag, dust, and gunk. And they come in different sizes and metal, for different size/type wire.

They only cost like 20 bucks, and I replace mine AT LEAST every 250 hours of use, or yearly wether it needs it or not.

I have found using flux core or cheepo wire will crud them up even faster.

 

[Old Iron]

Use one of the wire lube felts with wire feed oil on it to clean and lube the wire before it goes into the feed rollers too.
They have a slit in the felt and just go over the wire before the rollers, you drip oil on it from time to time and it lubes the liner for smoother operation.

 

[meteorman]

liner

I did just replace the liner, because I had read that it's a common problem.

I've never heard of the felt wheel thing. I'll have to check into that at my local supply store.

If the tension is too tight, what would it do? just stop? Maybe it's too tight.
I'll have to play around with the wire tension. It may need to be adjusted.

I am a total rookie at this. Thanks for the suggestions and questions.

 

[Torchie]

Too tight on the tension can groove the rollers as well as flatten flux core wire if that is what you are using. Also can leave a flatspot in the wire while the welder is at rest.
Check your manuel for some sort of tension setting advice. Should be something in there or google it and see what comes up.
My machine works well. Most of the problems are just me[S
Torchie.

 

[Sunnybeach]

I am also a rookie welder and have had intermittent problems with the machine I have... but the biggest problem is that I went cheap with a 110v machine.

There were lots of considerations -- cost, lack of 220 in the garage, etc -- but now that I am getting a little better it sure would be nice to melt thicker metal and have a longer duty cycle.

Maybe next time around.

 

[meteorman]

'fixed'

duh. I finally got a new roll of wire for the welder and it seems to be working fine I had put a 'new' roll of wire that I inherited in the machine, but it was apparently either the wrong kind or too old? or something.

I ordered a new roll of brand name wire for the application (basic mild steel etc)
and it's working great!!
thanks for all the suggestions and patience.
it's usually the simplest thing. that I overlooked at the start.