I am having problems with my power supply for my cnc mil. The machine is 90 something model. Checking the transformer on the machine, I have 120v input, but zero out put. I called signal transformer comp, they made this particular transformer and it seems it is no longer available, obsolete, but they will make me one if I can wait the 20wk lead time. Finding a substitute is proving impossible because this transformer is a 26v-52v output. Best I can up with, and this was thru signal transformer company, is a 24v/48 volt transformer. I have searched ebay to no luck. In the mean time, I took the transformer out of the machine and while I had it on the bench, I decided to hook an extension cord to it, just to see if I could figure anything out. Well, bang, it fired up and started humming, something it wouldnt do while installed in machine. Voltage shows 28v and 56v output. My question is why does it work on the bench, but not in the machine. I have verified the power going to the transformer several times.