Dialarc 250 HF Won't Light Up

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I bought a used Dialarc 250 HF in October, all went well,(the machine worked), until a week ago. Striking an arc is intermitent. Sometimes up to an inch, other times impossible to strike except scratching, this isn't good with aluminum.I cleaned and gapped .008" the arc points, I thought I had cured it, then worse than ever.Local welding supply recommends a fellow 8 hours away round trip. Dyna Steve had a service manual I would gladly pay for a copy.Any help would be appreciated, I'm making do with a Diversion 180. It's like logging with a hatchet.
Reply:Willie,have you tried different tungstens?  Just curious.  I know it's not fixing the problem, but my Dialarc won't start pure tungstens anymore.  I switched to those E3 (purple) and it's doing ok.I wondered if the problem isn't in the footpedal?Lincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:Need to know a few things. Does it stick weld normal? What type of TIG torch, Air or water cooled? When you had to points out to clean, what did the surface look like? smooth or pitted? Being able to stick weld tells us most the welder is OK. and we have only a HF arc start problem.Water cooled torches have a bad habit of breaking the power cable inside the return hose.Causes hard starting to HF only with no weld arc, to intermittent operation. If the HF points get to pitted, Even though they may arc good, They don't make good HF that will fire the torch  correctly. Next what does the arc at the points sound like? soft buzz or hard crackle? Soft buzz like a neon sign light is an open HF capacitor. What we want to hear is the crackle.With good arc at HF points and gaped right. We will need to look at the HF Path through the torch and back. With the welder turned off use an ohmmeter and check from each weld terminal to the case. Should measure high ohms or open. A short or low ohm is bad. You may have to check all the resisters and capacitors that live between the weld terminals. See your machine diagram. This network is part of the HF return path. T3 is the HF coupling transformer,
Reply:Originally Posted by ccawgcNeed to know a few things. Does it stick weld normal? What type of TIG torch, Air or water cooled? When you had to points out to clean, what did the surface look like? smooth or pitted? Being able to stick weld tells us most the welder is OK. and we have only a HF arc start problem.Water cooled torches have a bad habit of breaking the power cable inside the return hose.Causes hard starting to HF only with no weld arc, to intermittent operation. If the HF points get to pitted, Even though they may arc good, They don't make good HF that will fire the torch  correctly. Next what does the arc at the points sound like? soft buzz or hard crackle? Soft buzz like a neon sign light is an open HF capacitor. What we want to hear is the crackle.With good arc at HF points and gaped right. We will need to look at the HF Path through the torch and back. With the welder turned off use an ohmmeter and check from each weld terminal to the case. Should measure high ohms or open. A short or low ohm is bad. You may have to check all the resisters and capacitors that live between the weld terminals. See your machine diagram. This network is part of the HF return path. T3 is the HF coupling transformer,
Reply:Originally Posted by dubl_tWillie,have you tried different tungstens?  Just curious.  I know it's not fixing the problem, but my Dialarc won't start pure tungstens anymore.  I switched to those E3 (purple) and it's doing ok.I wondered if the problem isn't in the footpedal?
Reply:What Steve suggested is interesting. So for some reason you have to ground out the electrode first, then HF will start like normal. I'll try that with mine.Sent from my XT907 using TapatalkLincoln SA 200Esab Caddy 160Thermal Arc 201TSMiller Dialarc HFI don't like making plans for the day because then the word "premeditated" gets thrown around the courtroom....
Reply:Don't ask me to explain. Some of these guys have forgotten more than I know.
Reply:Originally Posted by Willie BYes I have tried tungstens, with the welder I probably got a quart to join my collection, pure, thoriated, E 3, ceriated, lanthanated, in 1/16,3/32,1/8. no detectable difference. The foot pedal maybe, but it works well all other functions. Once I strike the arc all is well. I did try something suggested by 7A749, Touch, lift, press the pedal. That works.Your help is appreciated.