My LPL takes an MR-16 type lamp and the standard pins are flat, but I've had bulbs that had round pins too, the socket in mine takes both.
The way I solved the no power supply problem for a Durst 1200 I set for VCP was to take a Chromega power supply we had with with an otherwise broken Chromega and connect it to the durst by grafting the connector from the dead enlarger onto the Durst's cord, after decyphering the power supply's pinout.
In the case of our 1200 there are only two conductors going to the head, so the fan is apparently fed from the same circuit as the lamp, at 24 V.
For your 401, you may need to do some wire tracing to determine what goes where. For example, my LPL's fan is line voltage, and the lamp runs from the 82 v power supply with 4 wires going to the head from the power supply.
The bulb type will tell you what voltage it needs (once you look it up on one of the bulb supplier sites). The fan, hopefully, will have a label on it identifying what it needs to run on, or else, a manufacturer and part number you can google.