2 Jul
2008
2 Jul
'08
12:50 a.m.
Roy J. Tellason wrote:
On Tuesday 01 July 2008 14:00, Jim Brain wrote:
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 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.
My apologies for the incorrect information. I would assume the C64 HD
PSUs (being the same as the C128 PSU, just a different plug, use the
same switcher design. I could swear, though, that the older
non-serviceable 64 PSUs are not switchers.
I have somewhere here in the stash a schematic for a MA701 PSU, that
looks to be a HD linear for the 64. I have a couple of the units. Is
the OP looking to just buy one, or is the design the big thing?
Jim
--
Jim Brain, Brain Innovations (X)
brain at jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com
Late in the game, CBM switched (no pun intended)
to switchers. I have a
C128 PSU that is a switcher. They were mounted in the same case, but
you can tell by the weight.
I don't recall ever seeing a 128 PS that wasn't a switcher. The 128D had it
inside the case with the computer, rather than separate in a "brick", but
it wasn't that different, just a little more spread out.