View Full Version : Need Help! Airco 300 Heliwelder IV Need to know Proper wiring

09-26-2008, 11:26 PM
I have a old Airco 300 Heliwelder IV machine. I have just ordered a new reactor pwb for replacement and apprehensive to power the unit up. I need to know what color wires go to the 25 Amp bridge rectifier mounted directly above the reactor board. There are four wires, colors are blue, white, red & black. I know the white & blue go to the AC terminals. :confused: Does anyone know the correct wiring for the red & black leads? I have a picture of the wires in question. If anyone knows some type of an answer, I would greatly appreciate your comment or suggestions.

Thank you for your time.

10-01-2008, 04:44 AM
Black is positive+ and red is negative-, just backwards of what you would think.

10-01-2008, 10:28 AM
Thank you for your reply. I just needed to confirm the wiring before I power the unit up. The picture shows what you have said. This must have been a mistake at the factory during production or it must have been made overseas.

Thanks again!