Miller 375 x-treme fires about 30 seconds then stops it doesn't stay running, no trouble lights...

https://www.youtube.com/watch?v=o5szBvrPx4s

if you welded to long and overheated when cools down will reset ----if on and were not welding then check and test thermal protector for failure

Hi:
There is no mention of the Thermal Dynamic's gun model, but i will suppose that it is a SL60 or a SL100 which are replacement guns for any model of plasma using the proper adaptor.
Your problem could be the start cartridge which go bad now and then when the gun is used as a replacement of a hammer to make the cut piece to fall.

The way to check if your start cartridge is in good condition is by checking the low part of the cartridge, push it up (or down depending on the way you handle it) it should freely slide inside and return out.

Good luck.

Some times when I use my plazma cutter its a cut master 42 .I would some times have to turn it off and turn it back on for it to work .And here lately all it does is air come on and off its like its has a heart beat and then have to cut it off again . I have replaced the tips and electrodes .And nothing .I have took thee electrode out and clean the white dust build up and works fine for a little while

the tech is probably pretty close to the cost of board,but you may have moisture in air that still wont take out the p.c..you have a warrenty on the unit,go to your local welding store and request a new one if refussed tell them you want to talk to the miller salesman which they should have no problem to set up.if not call miller direct in appleton wisc.they are good people.

it sounds like the afc the fan control not working could be dust on the afc

Try this site

www.Millerwelds.com

go to www.millerwelds.com/products/plasma you will find the info you need there

HI.

Follow this step to keep running your sunfire.
1 - Be sure the battery is full charged.
2 - Is better if you put a battery charged
3 - Turn the key to run position and tray to start the car and leave with the key in run position,
With a watch let pass 10 minutes no less. you gonna see the security light flashing and stop flashing after 10 munites.
4 - After 10 munites turn the key to off position during 30 seconds, with watch on your hand, OK.
6-- After the 30 seconds try to star the car

I hope this solve your problem.
Please letme know.

Thank you for use fixya.

To my understanding,the first 30 seconds is a test mode when the blinder will react to a tv remote,after wards the light will remain green until a true laser attack.