On May 16, 16:22, Tony Duell wrote:
> [BBC power supplies]
> I'd love to see circuits for all the versions, or at least circuit
> descriptions. On the other hand, Acorn PSU schematics are generally hard
> to find for some odd reason.
I never saw schematics for any of the black ones; I've got the diagram for
the Astec as you know. I once did have a note of what the chopper was --
or rather, I had a part number that worked. I worked for Computer Field
Maintenance for a while, and we used to repair them (though they didn't
actually fail very often. They seem to be pretty robust). BSR made a copy
under license, but the BSR ones don't seem to be so good -- not so well
regulated, for a start, so not so tolerant of overloads.
> All my Beebs have the traditional Astec SMPSUs. BTW, does anyone know
> what the chopper transistor is in these units? It's the same in virtually
> all Astec supplies - a TO3 can on a small PCB/heatsink mounted at right
> angles to the main board. There is never a number on it.
All I can remember is that it's NPN, I think. I'll dig through some old
files if I can figure out a way to read the old winchester backups, and
see...
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
Received on Sun May 16 1999 - 15:30:47 BST