I have H21 code problem on Miller Big Blue 400 x Pro

[aurasdz]

Hello, I need your help, I have H21 code problem on Miller Big Blue 400 x Pro, No welding output; the power
of the generator is correct at the
AC current.
Please if anyone have the solution I would be grateful.

[Kpack]

You’ll have to look on the Miller site for your manual, you’ll need your serial number.
I’m not the best to give advice but I would start with easy stuff like a fuse somewhere in the weld circuit. I’m not sure but hopefully the there’s two fuses, one for weld and one for ac electric output.

[Kpack]

This is out of my bobcat manual, you should have something like it

[Weld dr]

You have a thermal device in IGBT module MOD-1/MOD-2 check the wiring going to PC1 If wiring is good replace MOD. Make sure you have some knowledge of the inside workings before you start testing the unit does not have to be running for this test. hopefully it not the mod kit they run around
$ 2,000