Update and Pictures: It's been a hell of a day! HP 9845/2x

Be warned that thr 9845 PSU is _very_ complicated, even worse than the PDP11/44 PSU (!). Anyway, the input circuit isn't too bad. There's a mains-frequency transformer (the laminated-core one on the metal bracket) that has 2 primary windings. They're in series for 230V, in paralell for 115V. The output of this transformer provides the startup supply. There's also the conventional bridge/doubler circuit with the 2 massive capacitors in the middle of the PSU mainboard to supply 350V DC to the choppers Anyway, the fans are connected in parallel with the startup transformer primaries. So on 115V they're essentially connected across the mains. There is a fuse at the back (10A IIRC for 115V) that I'd check first, otherwise look at the wiring on the back panel, the barrier strip on the side of the PSU casing (be warned that the screws that hold the cover over that go into loose nuts inside the PSU casing, so pull the PSU module first), etc. This is one of the not-too-complicated parts of the machine. -tony