Lincoln PT 185 problem

admin

I've been doing quite a bit of Tig welding of stainless 304 with a Lincoln PT 185. I'm welding up .065 wall 2.5 and 3" exhaust systems for a customer who operates a custom car shop. This is his welder and it has been a decent machine for this job until now. For the last two days it has been intermittently failing to start at low amps. This is usually after I have run a bead most way around a joint fairly steadily..Welding amps are only around 45-50 so I cannot imagine that this is a duty cycle problem.When the problem occurs, full pedal will not light the torch initially. Usually after three or four tries it will finally start again but only with full pedal (with the panel set for 90 amps at full pedal in this instance). Once the machine finally lights up, it can then be backed down in amps and operates normally from then on , until the next time the problem in encountered.I've used this machine a lot over the past few months and never experienced this (or any) problem with it until now.any ideas?The machine is just nicely off warranty.
Reply:Does it have points for the hi freq starting?  IF it does (my syncrowave does), they may need cleaned or adjusted.My name's not Jim....
Reply:touch the tungston to the work (with foot pedal OFF)Then try again with normal gap.Works on my 175
Reply:thanks for the tips, will try/inspect and let you know how it goes.Glen
Reply:If your TIG welder has hard arc starts on the second start. I have an easy fix.If the first time you try to weld the arc starts normal and weld fine. Then the second arc start just won't fire unless you tap the torch on the weld metal. If the gas cup or tungsten have touched the weldment and now the torch fires and starts normal until you stop and have to do it again.This is what is going on. A thin coating has developed on the face of the spark gap points.Take the points out of your welder and go to your wire wheel and clean them up.Blow the dirt and dust out of your welder and reinstall your points with the proper gap.Figured this out with the help of one of the older tech support guys at lincoln who has now retired. Good luck guys.
Reply:thanks to all for the advice given, it was spot on.  We cleaned the points and the problem went away.Glen
Reply:your is about the forth machine i know of that had this problem.You would not believe what I went through to figure this out. Talked to several techs at lincoln that did not have a clue. Caught up with Jerry and he remembered one other machine that acted like these. And suggested cleaning the points. Cleaned them up and the welder worked normal. Had two of these almost back to back.
Reply:I have a PT175 that has done this same thing on occasion. I haven't taken the time to actually consider fixing it, but it's only once in a while that it happens. I guess I need to get out to the garage and take mine apart and clean it up and see if it fixes the issue.Thanks for the guidance guys!KevinHobart Handler 210Tweco Fabricator 181iLincoln Squarewave Tig 175