SOME of the later S100 systems had regulated supplies and then ditched the board regulators, usually leaving a place to put a regulator with just a jumper wire in place of the regulator.
tony duell <a...@p850ug1.demon.co.uk> wrote: >> > >> > ... Which also may well not be RML original. The 380Z has a regulated PSU, >> > S100 has separate regulators on each board and an unregulated PSU. >> >> Indeed, although I do recall a heatsink mounted externally on the back of >> the chassis (where the fan would be on the later hardware) with the early >> machines - I just don't know details of the internal PSU. > >I was going to say that that heatsink didn't look original, but fortunately I >kept my mouth shut and didn't insert my foot :-) > >I've only seen the later black 380Z's with built-in 5.25" drives, first at >school >and now the one I own. On those the PSU is entirely internal, it's a little >chassis that fits round the mains transformer and carries a PCB of >recctifiers, regulators, etc. For some odd reason the schematic of that is not >in the manual, I guess I should draw it out sometime. It's not complicated. > >Thinking about it, I do wonder what that heatsink/regulator is doing in an S100 >system. Most likely it is the original RML supply and somebody has connected >to the unregulated inputs to its regulators > >-tony >