I am in no way trying to say you didn't check this(on the contrary, it is something that happened to me), but make 100% sure there is a good ground. I had issues with intermittent ignite issues and it turned out to be simply a ground issue.

 

He told me he had tried it; I have not tried it myself, and you are right - bad ground on plasma cutter is like bad exwife that won't go away - I will give it a check .... I think not that simple, but until I try it myself, I won't know for sure - thanks ... one more tic in the box.
Take care and thanks -

 

I might be able to help you with an manual. The serial number looks like old century.
Look for a model number on the front of the welder where the spects are. should start with 118-xxx. also does it have a YA or an M number on it? One good picture of the front panel will help.
You can call snap-on and ask them for a manual and who made it for them.
The only blue point plasma's I have worked on, were made by Cebora. On them the pressure switch fails to close. You can pull the rubber cap and use a Allen wrench to readjust it.
Most plasma safety pressure switches are set to around 40 psi

 

Thanks! Will look into that! I have not had a lot of time to dig into this (been traveling for work), but anything will help! Thank you again.