Yes, we are looking for mistakes. If you look at the schematic you can see UP-3 should be tied to +12 with a wire, so It should measure the same as UO-3. So somehow it is getting the higher voltage - maybe under the board or if some other pin is tied to +48 and the part is shorted it could feed back. When you remove the part measure all the voltages on that IC. None of them should be over 12 volts.