RM 380Z Special Control Unit (?) - test-drb@ccmp.vtda.org

1 Aug 2015

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 <ard at 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