30 Jun
2008
30 Jun
'08
5:42 p.m.
On Monday 30 June 2008 16:19, Eric Smith wrote:
Roy wrote:
The 9VAC supply is fed into a voltage doubler to derive the regulated +12V and
a separate +5VDC supply, and I don't think that either of those 9VAC lines
can be grounded. I have some fairly complete schematics around here
someplace, but I'd have to find 'em to be able to explain it in more detail
than that.
If you have a schematic of the C64 available, try envisioning what would
happen if you grounded either of those 9VAC lines, as in what components
would end up shorted out. :-)
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
The 9VAC has to be a separate transformer winding
from the one that
provides the +5VDC eventually, because of how it's used...
Why does it require isolation between the 9VAC and the +5V DC? It's not
obvious to me from the schematic.