Originally Posted by
lucas
That short on the Y Vref is a good indication.
I would guess that the Y driver chip is shorted internally and pulls both the Vref and +5 down.
You could compare the resistance of all chip pins with each other, if one or more pins of the Y chip is different then it's probably blown.
To be sure you could cut the 5V pin of the chip or the PCB trace to that pin (do it in such a way that you can resolder them back) and then measure again.
What supply did you use, you mentioned 42V IIRC, this may be on the limit.