Old Linde TIG machine does not want to start an arc

The machine is a Linde Heliarc 250HF. I'm assuming it is from the early eighties like a lot of stuff in this shop.

It does not want to start an arc, on both AC or DC.

Last time I experienced this it was with a miller machine that we had at my other job it was much newer. I called miller and described the issue and they said it needed new HF board. Sent it away and it worked great once we got it back.

So, given that experience I'm assuming that this machine has a HF problem. I called ESAB and they said to check and make sure that the HF switch works before trying to get a new board.

Anyone got anything to help me trouble shoot this?

Am I wrong to assume that the arc not starting is a high frequency issue? I don't really know how welders work per say, just know how to use them. Of course, I don't consider myself an expert on that either.

I have handed the board off to an electronics expert in the building and he is gonna look at the switch and board to see if there is anything obvious he can fix.

Thanks,
Joey

Its an outside possibility that there is a fusible link on the water line- assuming it has a radiator-
this is a small brass block, that the main water line from the radiator is screwed into, and the torch cable comes out the other side of.
It has a tiny copper fusible link, and, if you try to run the torch with no water, it melts. Then, no power to the torch, until you replace it.

Have you tried hooking up a stinger and doing stick welding with it?
Which, of course, does not need or want HF.

does not have a radiator. It has a little solenoid circuit job to run water through (supply your own coolant flow) that I am not using.

The welder will work, I just have to scratch start it. The arc won't jump to the work unless the tungsten is touching it.

Does this have high frequency points? Its possible that they're worn out of spec or just plain dirty. You probably have to pop the cover off to find out. I know I cleaned them in an old Linde UCC-305 I used to own and it made arc starting a lot easier.

Yeah they talk about those points in the manual. They said to make them clean and use a feeler gauge so they are .007" to .010" apart, which they are.

They look clean, no dirt feeler gauge passes through with no debris coming out. I suppose I can take them out and polish them if need be?

vonblowseph said:

Yeah they talk about those points in the manual. They said to make them clean and use a feeler gauge so they are .007" to .010" apart, which they are.

They look clean, no dirt feeler gauge passes through with no debris coming out. I suppose I can take them out and polish them if need be?

Click to expand...

With high frequency switched on, if you kick the pedal do you get sparks in the air gaps? Can you hear a high frequency whining noise?

If not it could be a problem with the switching circuit that turns on the coil that generates the HV, a bad HV cap or a bad connection/tracking to ground that the HV is leaking somewhere instead of going to your tig torch like you would like

Oh yeah thems some good suggestions to find out what's wrong with this mint green beauty.

Soon as I get the board back from my electronics dude I will try that out.

Thanks Green buggy!

Have you tried to scratch start the arc? This will tell you if you are getting current to the tungsten and if it is in the HF circuit.

Also as mentioned I thought these things had an arc gap for the HF that needs to be cleaned and check the clearance with a feeler gage. Metal dust and stuff can contaminate the contacts as they are used.

My Hobart Tigwave 250AC/DC did the same thing a few times on me. First time was operator error. Somebody before had cleaned the panel with something that smeared the labels to the point they were nearly unreadable. I finally looked up a pic of the panel (now saved on my desktop and printed out for reference every few months) and what I thought said "Start" on the HF control actually said "Stick". HF start/continuous was on the other side.

Second time, it was the cannon plug on the pedal. It had been overstressed one too many times and one fo the wires had pulled out of the connector. 15 minutes with a solder gun and it was back perfect. Third time, after a year or so of service, it was the points, as above.

I used to run one of those Lindes at the museum I worked at. Loved that machine. It's what I actually learned to TIG on.