Miller Syncrowave 250 no output

[BradF80]

Hi all,
New to the forum. I have an older Miller Syncrowave 250
Serial # JJ459764

I bought the unit non working and have been trying to diagnose it.

I'm an automotive electrial technician so I know my way around a wiring diagram. I've downloaded the manual and tried testing what I could. My biggest issue is voltage. I'm just unsure at what voltage many of these circuits run on.

I've been focused on the amperage circuit since that would make sense as to why the machine doesn't have any output. I've tested the amperage potentiometer which goes from near zero to 1k ohms resistance. The potentiometer is a 1k resistor and tapered fine using my fluke multimeter.

the input voltage to the potentiometer seemed like an odd voltage and that's where my question is.

the input voltage I got from the potentiometer is just about 3.5 volts.

Does anyone know if this voltage is correct?

i suspect the PC1 board is bad since it is the most common cause of no output from reading the forums. I just want to ensure I'm not throwing parts at another problem.

Any input would be greatly appreciated!

[BradF80]

Also, I cleaned the main bar contacts and put some fresh dielectric grease on them.

there is another issue I noticed. The spark plug gap for the A/C output is non existent. Would this cause any issues working with D/C?