You did a great job Tobias. Don't sweat on it breaking. As long as you've documented everything, I'm confident it can be fixed with no problem. It was a really lucky fault though. Had something on the hybrid circuit blown.... that wouldn't have been so good.
As for the calibration software, Tony's one drive is great. If you want, there is the raw file in this group as well. I wonder what the path to failure was? You had a blown relay, a bad YTO driver, and of course that shorted feed thru capacitor. The cap was shorted in the first place before you put 1.5 Amps thru it.
Heres my theory:
??? on the power supply section surged? > breaks relay but goes to YTO driver > components break on the YTO driver > something on the YTO driver causes that feed thru on the YTO to become shorted.
How other components were not affected will be a mystery. Maybe they were? It can be called case closed if you can find the original fault and its pathway. Till then this is good enough.
-Lex
PS: I can explain what happened when that feed thru cap became 20Kohms before it became a 1 ohm short again. Normally in the AC condition, any incidental AC signal (probably from either the YTO driver or the YTO itself is suppose to pass thru to grounded case from the coil via the feed thru cap which acts as a short for AC. In the DC condition the cap is an open circuit and instead heads to the YTO driver via the wire connection. However since you put high power thru the cap the first time, it turned into a 20Kohm resistor. What this ended up doing was fixing the short to ground for DC but now you have both the DC and some AC signals mixed together going thru the wire of the -40V supply, the coil (has less impedance than 20Kohms), and the YTO driver. That is why you saw the unstable results with the YTO loop. Anyways, that feed thru cap had to be replaced one way or the other since there needs to be a short to ground case for AC but not for DC. DC goes thru the wire.
