Commodore 64 Power Supply

[Tony Duell]

> OK, I stand corrected.  I finally got home tonight, and was smug enough 
> to go out and pull the units.
> 
> First, the lightweight PSU I have with a C128 is not a C128 PSU at all, 
> but a A500 PSU.  I am sure we tested the PSU with a C128 last week (we 
> were going through the units prior to the C4 CBM EXPO this past 
> weekend), but I'll have to check.  The reason's it is so light is it 
> only provides DC on the outputs.  5 and +-12.  It simply chops mains to 
> get what it needs, I would guess.

The A500 PSU is, indeed, a conventional switcher. Rectifies the mains, 
chops it, feeds it into a transformer, rectifies the output, and has 
control feedback fro mthe 5V output to the chopper controller for 
regulation. The 12V outputs just 'tag along'.

I thought it was very foolish of Commodore to have 2 PSUs with different 
outputs that used the same custom connector (a thing that looks like a 
square DIN plug). IIRC plugging the Amiga PSU into a C64 does no daamge 
(I can't remember if the machine basically works or not), pluggling the 
C64 PSU into an Amiga can do damage (applying 9V AC to DC rails).

> 
> The other C128 PSUs are heavy as a common brick, and Roy looks to be 
> right.  They have what looks like a switcher under the huge transformer. 

That's what my C128 PSU has.

-tony