Lincoln will not support the pro 55 plasma cutter

[bigironmike]

I purchased a used pro 55 plasma cutter it fires up air get through the gun but no arc? Had it diagnosed at the only repair shop in Tucson Weldrite welder repair, output board bad. No longer ava. So I find a used board on ebay install it, same problem. I had my father who went through the entire board tested each circuit looking cold solder joints or bad components board is fine. Has anyone else have this issue? is there a solution or something else should be looking at that i have missed? It seem to be the recommended machine for my antiquated PlasmaCAM DHC table. I just want to cut some metal

[weldguy]

Check out section E-2 pdf the attached manual if you haven't already. Can you match up the behaviour of the status indicator lights on your machine to any of the listed behaviours in section E?

Pro55.pdf

[tcaudle]

In any electronics assembly that fails its most likely the components that take the most stress (voltage or current wise) IN the case of plasma cutters the OUTPUT devices (normally big IGBT modules ) that carry the full power would be the first thing to check. The board that controls them COULD be involved but playing probabilities, it's more likely the module(s). You may have to dig and find part numbers on the devices and if those are obsolete use the specs to find a substitute. A module can be tested statically if you have a meter that can test diodes or you know how a diode shows values on an ohmmeter.

Here is a link to an article on how to test an IGBT module out of the circuit.
https://www.gprectifier.com/news/how-to ... 66357.html

Unless you REALLY know what you are doing do not work on a plasma unit with it connected to the AC mains ....it can killyou!