THC Voltage

Yeah, that’s what I suspected. I’ve seen a rash of failures involving L1 on the Powermax45 XP voltage-divider board. With the cover removed, you’ll see a gray two-conductor cable running from the CPC assembly to the small divider board with the DIP switches used to select ratios such as 50:1.

L1 is a four-pin common-mode choke. The positive and negative conductors each have their own winding, with the same number of turns around a shared ferrite core. When it burns, the two windings short together, connecting the divided-voltage positive and negative outputs. That collapses the output to zero, which matches what you’re seeing.

I’ve repaired probably 8–10 Powermax45 XP units with this failure over the years, including the one on my own shop machine. I desoldered the failed choke and separately bridged the two signal paths with insulated jumpers. Each of those motion controls already had analog isolation on its arc-voltage input, and L1 is primarily there to suppress common-mode noise.

On the older boards you can usually see the burnt windings. If I remember correctly, newer boards use a different part with a molded case that hides the windings. I haven’t seen this same pattern of failures across other Hypertherm models.

Since you need a handheld unit around the shop anyway, upgrading may still make the most sense. If you decide to repair the 45XP, L1 would be the first component I’d inspect and test with the machine unplugged and fully discharged.