I started a thread requesting a service manual that evolved into troubleshooting. I can't delete that thread, but I'd like to consolidate it into a "troubleshooting" thread. I'll paste the relevant parts into this first post and this way it will have an accurate title.

Ok... I finally got the machine hooked up. For those of you who requested the usage stats they are - 415 hours and 135308 cycles. The Unit SN is LH500798L
I completed a factory reset per the owners manual.

Today I tested both AC and DC and found them to be functional using the Lift Arc method.

I checked and cleaned the HF points and set them to .010. HF did not work at all no matter the pedal position or AC/DC. What is my next troubleshooting step?
I appear to be the only one with that info, but it won't help you.

Only 2 checks to make

RC1 check for 325VoltsDC bewteen RC1-1 to RC1-3, unit on at idle

RC2 check for +15 volts DC between RC2-1 to RC2-2 HF off
Check for 0 volts HF on

Or 700HZ betwwen RC2-1 and RC2-2 HF on

If that is there, all is happy and you need a new PC-7 Replacing parts on this board is probably NOT a good thing. as it may dynamite the rest of the machine.
I was finally home enough time to check the welder as requested. The results are below:

RC1-1 to RC1-3: 321VDC stable
RC2-1 to RC2-2: 0 volts pedal up or down
RC2-1 to RC2-2: Frequency is unstable when pedal is down and reads in the Mhz (most likely induced voltage from RF)

During testing the HF worked intermittently (for the first time) and gave both a very strong and sharp crackle for the first few minutes and later on it was about half as loud before stopping. DC voltage never showed on the RC2-1 to RC2-2. I wore rubber linesman gloves and welding gloves and wiggled the RC2 and RC1 wires while depressing the pedal to see if I had any loose connections. That did not change my results.

If anyone knows how to troubleshoot further I appreciate the assist. Is there a component I should check on the PC-6 tracing it back to the RC14-1 and RC14-8 on the PC6 board? What outputs the 15VDC and 700Hz signals?