Lincoln precision rig 275 does not arc sometimes

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Does the pt275 need to warm up? Sometimes when I start it up it will not arc for a few minutesJust makes a hissing noiseAlso I typically only make small 1" square tube thin wall AL welds that only take 20 seconds maxThe other day I was doing long welds maybe 2 minutes long at 100 amps and then had the same issue Has to wait 3 or 4 minutes before it would arc again Any ideas?
Reply:We had a new PT 375 at the high school I was helping out at.It arrived DOA. No arc in tig or stick mode. Argon would not flow in tig mode and no arc. Machine would turn on but no response.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by AluminumWelderDoes the pt275 need to warm up? Sometimes when I start it up it will not arc for a few minutesJust makes a hissing noiseAlso I typically only make small 1" square tube thin wall AL welds that only take 20 seconds maxThe other day I was doing long welds maybe 2 minutes long at 100 amps and then had the same issue Has to wait 3 or 4 minutes before it would arc again Any ideas?
Reply:Yeah, what Mauricio said. Blow out the arc gap.  My 175 does the same thing when it needs some attention.Harbor Freight Inverter 130 amp DC stick/tig (sold, really!)Lincoln Square Wave Tig 175 AC/DC stick/Tig
Reply:I've never done any maintenance on the machine is there a video or instructions some where on how to do this?
Reply:Originally Posted by AluminumWelderI've never done any maintenance on the machine is there a video or instructions some where on how to do this?
Reply:Originally Posted by AluminumWelderI've never done any maintenance on the machine is there a video or instructions some where on how to do this?
Reply:I have never had to adjust the gap. My PT275 is several years old already. These guys may be giving you the correct answer, I just have not had to do it yet.But my first thought was that you had the pre-flow set to max or something. I am interested to hear the final result. Keep us posted.Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:Another possibility is leakage of HF current. Damaged torch cables, cracked insulation, or excessive dust inside the machine can shunt the HF to ground, making starting difficult.JohnA few weldersA lot of hammersA whole lot of C-clamps