10 Aug
2012
10 Aug
'12
3:05 p.m.
I finally got hold of that PSU-less C64 that I mentioned on the list a few
weeks ago, followed by a 9VAC PSU to test it with. Other than needing the
VIC-II and associated ICs re-seating I've not encountered any problems
(I've not tested the 1541 yet though due to lack of a cable).
Anyway, I'd like to sort out a better PSU for the machine itself until I
can get a genuine one from somewhere - does anyone know what a reasonable
max current draw on the 9VAC lines might be? (This is an original
'breadbox' machine)
The wall-wart 9VAC PSU that I found for testing is only rated for 400mA,
which I suspect might be on the low side; I've seen claims of needing 1A or
more, and http://www.hardwarebook.info/C64/128_User_Port only states 100mA
max for the user port, suggesting that the machine itself might require
quite a lot under certain conditions.
cheers
Jules
10 Aug
10 Aug
3:42 p.m.
On Fri, 10 Aug 2012, Jules Richardson wrote:
I finally got hold of that PSU-less C64 that I
mentioned on the list a few
weeks ago, followed by a 9VAC PSU to test it with. Other than needing the
VIC-II and associated ICs re-seating I've not encountered any problems (I've
not tested the 1541 yet though due to lack of a cable).
Anyway, I'd like to sort out a better PSU for the machine itself until I can
get a genuine one from somewhere - does anyone know what a reasonable max
current draw on the 9VAC lines might be? (This is an original 'breadbox'
machine)
The wall-wart 9VAC PSU that I found for testing is only rated for 400mA,
which I suspect might be on the low side; I've seen claims of needing 1A or
more, and http://www.hardwarebook.info/C64/128_User_Port only states 100mA
max for the user port, suggesting that the machine itself might require quite
a lot under certain conditions.
There is a bunch of discussion about this over at the midibox.org forums.
They've come up with a couple designs for replacement linear supplies and
have specced out some switchers.
--
David Griffith
dgriffi at cs.csubak.edu
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12 Aug
12 Aug
11:41 a.m.
On 08/10/2012 02:42 PM, David Griffith wrote:
There is a bunch of discussion about this over at the
midibox.org forums.
They've come up with a couple designs for replacement linear supplies and
have specced out some switchers.
Thanks - I've found a few threads over there related to PSUs, so will have
a read through them.
I'm pretty sure I've got an ex-PC PSU somewhere in the junk pile with dead
caps on the +12V, which might make for the basis of a nice little 5VDC
supply for this C64 if I were to go the non-original route; it's just the
9VAC side which is a bit of an unknown, and whether my little 400mA supply
will cope.
cheers
Jules
10 Aug
10 Aug
4:59 p.m.
Anyway, I'd like to sort out a better PSU for the
machine itself until I
can get a genuine one from somewhere - does anyone know what a reasonable
max current draw on the 9VAC lines might be? (This is an original
'breadbox' machine)
I'd worry less about a genuine PowerSupply, and more about getting a good
one! A few years back I got a good one off of eBay. It's a 3rd party
supply noted for being repairable, and being able to provide more current
than genuine Powersupplies. The genuine Commodore PS's suck.
The wall-wart 9VAC PSU that I found for testing is
only rated for 400mA,
which I suspect might be on the low side; I've seen claims of needing 1A
or
more, and http://www.hardwarebook.info/C64/128_User_Port only states 100mA
max for the user port, suggesting that the machine itself might require
quite a lot under certain conditions.
Just how much depends on what you have plugged into it. IIRC, one of the
big power drains is an REU.
I really need to figure out how to find space to setup my main C64 in my
Office! I miss being able to use it!
Zane
12 Aug
12 Aug
11:36 a.m.
On 08/10/2012 03:59 PM, healyzh at aracnet.com wrote:
Yes, although my only experience related to them was with a Plus/4 with a
dead PSU many years ago, which became a futile exercise in removing potting
compound! They do seem to have a very bad reputation, though.
I suppose I quite like things to *look* original even when they're not, so
I wouldn't be against finding a dead PSU and fitting it with more reliable
innards. Of course it's hard to justify buying a dead PSU and paying
shipping costs, only to throw away the heavy bit when it arrives :-)
Well, I don't really have any plans to expand it - I'd probably only ever
use it with the 1541, display and possibly a joystick (although I was never
a big fan of joysticks 'back in the day'). I suppose I can't rule out the
possibility of it becoming a 'hackable' machine, but I've got 6502-based
card/backplane systems in overseas storage which will fill that desire one
day when I can get them shipped over to me.
I'm just not sure how close to the limit my 400mA supply is. Perhaps it's
OK to assume that if it's working with it now, it will continue to do so so
long as I don't add anything that uses the 9V, and I can package that PSU
into a box alongside a 5VDC supply, but I don't like assumptions if I can
avoid them.
Anyway,
I'd like to sort out a better PSU for the machine itself until I
can get a genuine one from somewhere - does anyone know what a reasonable
max current draw on the 9VAC lines might be? (This is an original
'breadbox' machine)
I'd worry less about a genuine PowerSupply, and more about getting a good
one! A few years back I got a good one off of eBay. It's a 3rd party
supply noted for being repairable, and being able to provide more current
than genuine Powersupplies. The genuine Commodore PS's suck. The wall-wart
9VAC PSU that I found for testing is only rated for 400mA,
which I suspect might be on the low side; I've seen claims of needing 1A
or
more, and http://www.hardwarebook.info/C64/128_User_Port only states 100mA
max for the user port, suggesting that the machine itself might require
quite a lot under certain conditions.
Just how much depends on what you have plugged into it. IIRC, one of the
big power drains is an REU. I really need to figure out how to find space to setup
my main C64 in my
Office! I miss being able to use it!
I'm glad to have this one. It's one of those systems that I've never
actively sought out, but quite wanted to have one day - a friend had one
back in the 80s and I recall being a little jealous of it at the time in
comparison to my Spectrum (which nonetheless wasn't a bad machine to play
games on or program).
Oh, the previous owner said that the (untested - it sounds like they found
everything in a dumpster) 1541 was broken as it rattled. That turned out to
be a pen cap kicking around inside the case, so fingers crossed the drive's
otherwise OK! Shame that whoever dumped it didn't dump any software to go
with it, though :-)
cheers
Jules
4328
days inactive
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dgriffi＠cs.csubak.edu -
healyzh＠aracnet.com -
jules.richardson99＠gmail.com