... but the power supply from a IIci/cx/vi/vx/Q650 may also fit, though you'll have to remove the motherboard from your IIsi to use a different type power supply to test it ...

Click to expand...

Near, but not quite. Only the IIcx, IIci and Q700 are deadset interchangeable. But all is not yet lost. The Service part numbers of several PSUs are given in the threads below, and a link to some PSU startup schematics. There have been recent interchanges about these matters:

http://68kmla.org/forums/viewtopic.php?t=1218&highlight=iisi

http://68kmla.org/forums/viewtopic.php?t=1792&highlight=psu

that are worth kuma's attention, and that tomlee59 has already arrived here is an advantage. Big Bird's comment about failure of soft power off is an interesting advance on a problem also recorded in this Forum.

de