Miller 125c problem

[bayleaf36ff]

I found an old miller 125c plasma cutter in my father in laws basement. it was apparently almost never used. I brought it home, and when I press the trigger on the torch, it fires right up and srarts cutting. But after about 3-4 seconds, the internal compressor shuts off and it quis working. let go of the trigger, squeeze it again, and you can cut for another few seconds before it shuts off. It acts like something is timing out, or some protection circuit is tripping? i have the ground clamp on the peice, and I admit the consumables are old and probably need to be replaced. The best price Incan find is about 100 bucks to replace all the consumables, and unless someone really thinks thats the problem, I dont want to spend the money. I have no need for the plasma cutter, just thought it would be fun to have since he didnt use it anymore. any ideas whats wrong with it?

thanks!

[Weezing]

I know this is going to sound strange. You may have one of two problems.

First check your ground lead by pulling on it. Look for the insulation to stretch indicating the conductor inside is broken. If ground lead is good, now for the strange one. screw the cap of 1/8 of a turn at a time until torch starts to cut. It has some thing to do with the electrode to tip distance and the shape of the plasma arc.

You might be able to stop the air leak by unplugging the fitting that's leaking, clean with a little solvent and push back together. Push in on the ring then push in on the hose turn and pull out. It should release.

Also you have a system that you can drag cut with. It is only a 12 amp plasma and the pilot and cut current is the same.

With larger machines, As a rule you can drag cut up to 30 amps. over 30 amps you need a drag shield that sets the cut height for you.