My Longevity WeldAll 200 PI will not start an Arc when trying to plasma cut

[minnfatz]

I was plasma cutting on my CNC table with with the WeldAll 200 PI I purchased 6 years ago. After cutting for awhile when the torch went to make a pierce, the arc started, then stopped right away, then tried starting again. It continued starting and stopping until I hit the torch off button on my CNC controller. The arc never did pierce the material. I thought the solenoid air valve was bad, so I put a new one on, but that did not help. I no longer get any arc and the digital current readout no longer says 30 amps, which is what it was set at, but reads anywhere between 81 and 84. I know the machine should only go up to 50 amps. No matter where I turn the Amp/current dial, the number doesn't change. I know that the air was dry, the current was set properly, and the torch was the right height above the material. I have 2 torches. One torch I use for CNC and the other for manual cutting. I have tried starting arcs using both torches, but neither work now. I'm guessing something has failed in my plasma cutter, does anyone have any idea what it might be?

Any help would be appreciated.

[acourtjester]

Finding out if anything works is the first step. If it welds then the main power generating section is working. Have you tried to use the welder part of the unit, stick would be the simplest. There are many different circuits used for the unit to work correctly, some are used for all functions and others are use for only some of the functions. When you try to trigger the plasma do you hear any clicking noise like a relay closing?

[minnfatz]

I hear the air solenoid click and air comes out of the gun. I also hear a switch or switches in the machine click. I have the cover off and can see both a green light, then red light turn on. You can see in this screen capture that a green and red led are lit up.

[acourtjester]

Trying not to be snotty but that does not mean a thing to me as I don’t have one of those units.
The things I told you to check are very basic and will tell you if other functions will work. This is a normal thing to do when trying to find out what may or may not be wrong.
It sounds like you did not let the magic smoke out of something, I understand many people don’t know electronics but doing a few checks (if you have had it for 6 years) you should know how to see if it will weld or not. There are many things that could be wrong from a simple switch to the thing is completely useless and you need to get a replacement.

[minnfatz]

I just haven't had a chance to get back to my shop and check to see if it welds and whatnot. I have been scrambling around finding another company to cut a bunch of stuff for a big job I have, since I won't be able to do it now.

I was just asking a general question, if people had any experiences with the arc starting and stopping, then not working at all. Since the amperage number is off the charts for this machine, I thought maybe someone might have an idea of where to start. It doesn't look like anything is burned up in the machine. I will try doing some welding this afternoon.

[acourtjester]

Ok not all electronic failures are from things burning up. You could have a switch or relay whose contacts no longer work this would be an open circuit. You said there was a red light this could be a fault, no power from a power supply or a missing signal. The list goes on this is why I asked if anything works. You could have one function that is affected and not others. It is like a car that the head lights don’t work but you can still drive it in the daytime. The fact you say the display does not change does not sound good, but many problems can be repaired it you can find some one to work on it and what that may cost.