Follow-up to Millermatic 175 problem

I got the machine back from the kid and looked at it for a while.
Nothing in earnest because I had to do some errands with SWMBO. While
we were out, I stopped in at a Miller authorized service center and was
able to speak to someone knowledgeable about the problem. I asked him
if he had free estimates and he said sure. You give us $108 and we will
give you a free estimate. Anyway, He asked me what the symptoms were
and when I told him he said that is sounded like what some of you are
probably thinking. Low voltage.
So I am wondering how that can be. I am using the dryer outlet in the
house and the dryer still works so that can't be the problem. I've used
it many times before. Used the same extension cord that I have used
many times in the past so that shouldn't be it. It's IS getting 240
volts damnit!!
So we get back and I start looking into it again. Sure enough it is
only getting 117.5 volts. WTF?!?!? SWMBO comes out and sez something
like " The last time you used it was at the kids house. Didn't you have
to switch the plugs over there?" Then the "AWWW SHEEEEEIT!" moment.
Sometimes I just hate that woman. :-) She has a way of doing that to
me. No I didn't remember that. I had to swap one of the ends of my
extension cord to match the outlet in his garage and then when I was
done I swapped mine back on again. Only I when I put mine back on I
inadvertently switched the white and green wires. SON_OF_A_BEEACH. I
fixed my cord and the welder works fine again.
Thanks for all your help anyway.
Wayne