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RE: [N8VEM-S100:1000] S-100 backplane request for help
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- Subject: RE: [N8VEM-S100:1000] S-100 backplane request for help
- From: "John Monahan" <mon...@vitasoft.org>
- Date: Sun, 22 Jul 2012 13:29:11 -0700
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Paul, 12A on the 7.5V may be a little on the low side unless you are just
sticking to 8 bits. The 16 bit CPU boards have 3A regulators and if you
have a dual (or more) CPU master slave setup, things could get tight. Agree
20A's is probably best. The 16 V lines are really only used for RS232 etc.
these days and even there, there are converter chips. So 1-2 A is fine.
John Monahan Ph.D
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
Behalf Of Paul Birkel
Sent: Sunday, July 22, 2012 11:37 AM
Subject: Re: [N8VEM-S100:1000] S-100 backplane request for help
While John has some great information on his backplane/ps page
one point that is missing is the proper power supply sizing for an 8-slot
The IEEE 696:1983 spec is silent on the allowed/anticipated ps-loading per
slot, but it seems reasonable to assume 1 A to maybe 1.5 A average per slot
on the 8V rail, max (most cards hosting a single 1A +5V regulator, with the
occasional dual-regulator configuration like the dual-IDE card)? That
suggests maybe 12A on the 8V rail, and we might guess 1-2A max on the +16
and -16V rails (since these aren't used much at all on modern cards)?
Am I way off-base here?
FWIW, here are what appear to be the most relevant Meanwell supplies (via
Power Factor, as pointed out by John) -- all of which can have their output
voltages adjusted upwards a bit to fit the 8 and 16 volt
http://www.power-factor-1st.com/g2-series/s-100f.html 7.5V, 0~13.5A $49.45
http://www.power-factor-1st.com/g2-series/s-150.html 7.5V, 0~20A $55.45
http://www.power-factor-1st.com/g2-series/s-210.html 7.5V, 0~27A $70.95
http://www.power-factor-1st.com/g2-series/s-40.html 15V, 0~2.8A $37.90
The 20A (second line) seems to be the cost-effective sweet-spot "with
Happy hunting :->.
On Sun, Jul 22, 2012 at 1:55 PM, Andrew Lynch <LYN...@yahoo.com> wrote:
> Hi! I?ve gotten a request for some help with the S-100 backplane PCB.
> Since it will probably require a PCB respin to fix I would like to
> gather up all the feedback and incorporate them as best I can. Thanks
> to Don Caprio there are some excellent builder instructions here:
> Please post photos of your completed working S-100 backplane systems
> on the wiki in the S-100 backplane folder. Actual builder photos are
> *very* helpful for new builders.
> There is a new file for S-100 backplane fixes and improvements here:
> Please edit with any issues you?ve encountered on how to fix and/or
> improve the S-100 backplane.
> The photos that are in the folder at the moment are getting rather
> dated so they should be retired to the archive as to not confuse any new
> Thanks and have a nice day!
> Andrew Lynch