Re: [N8VEM-S100:1004] S-100 backplane request for help

[Jack Rubin <jack....@ameritech.net>]

Sorry - I haven't been following this thread, but especially when building new 
boards, why not scrap on-board regulation and just run +5 and +12 volts on the 
power rails? Cuts cost and heat rejection. Modern switching supplies are 
well-enough regulated not to need the margin of the old linears. Godbout (and 
others?) went to this strategy on their later systems.

Jack



----- Original Message ----
> From: Terry Sare <ts...@sareusa.com>
> To: n8vem...@googlegroups.com
> Sent: Mon, July 23, 2012 8:09:34 AM
> Subject: Re: [N8VEM-S100:1004] S-100 backplane request for help
> 
> Paul,
> 
> I got two of these -- $13.29 each plus ~$14 shipping, adjust up to  16.5 
> volts.
> 
> http://www.powergatellc.com/mean-well-rs-25-15-power-supply.html
> Output(s)      15.0V @ 1.70A
> Power     25 Watts
> Dimensions      3.08 x 2.00 x 1.10"
> Operational Efficiency      83.50%
> Operating Temperature     -20~+70°C
> 
> The old  transformer and p/s in my 22 slot chassis weighs around 20 lb -- 
> the 3  switchers together weight about 4lbs. Nice.
> 
> terry
> 
> 
> On 7/23/2012  12:03 AM, Paul Birkel wrote:
> > Terry:  Excellent pointer, and more  cost-effective supplier :->.  What
> > did you do about the 16V  rails?
> >
> > John:  I haven't seen any 16-or-more-bit boards yet  and failed to
> > consider their impact; thanks for reminding me about the  near future
> > (coming soon to a backplane near you ...).
> >
> >  On Sun, Jul 22, 2012 at 4:47 PM, Terry Sare <ts...@sareusa.com> wrote:
> >> And  for those of us that want overkill I found this
> >> 1 x 350 Watt, Single  Output, SE-350-7.5 from Mean Well (SE-350-7.5) = 
>$48.29
> >>  http://www.powergatellc.com/mean-well-se-350-75-power-supply.html
> >>
> >>  Output(s)       7.5V @ 46.00A
> >> Power   350  Watts
> >> Dimensions      8.46 x 4.53 x 1.97"
> >>  Operational Efficiency  80.00%
> >> Operating Temperature    -20-60°C
> >>
> >> Total with shipping was around $62 so not  bad.
> >>
> >> Terry
> >>
> >> -----Original  Message-----
> >> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com]  On
> >> Behalf Of John Monahan
> >> Sent: Sunday, July 22, 2012  3:29 PM
> >> To: n8vem...@googlegroups.com
> >>  Subject: RE: [N8VEM-S100:1001] S-100 backplane request for  help
> >>
> >> 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
> >>
> >>
> >>
> >> John Monahan  Ph.D
> >> e-mail: mon...@vitasoft.org
> >>  Text:    mon...@txt.att.net
> >>
> >>
> >>  -----Original Message-----
> >> From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com]  On
> >> Behalf Of Paul Birkel
> >> Sent: Sunday, July 22, 2012  11:37 AM
> >> To: n8vem...@googlegroups.com
> >>  Subject: Re: [N8VEM-S100:1000] S-100 backplane request for  help
> >>
> >> While John has some great information on his  backplane/ps page
> >>  
>(http://s100computers.com/My%20System%20Pages/The%20Box/The%20Box.htm#The_Po
> >>  wer_Supply),
> >> one point that is missing is the proper power supply  sizing for an 8-slot
> >> system.
> >>
> >> 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
> >> bus-targets:
> >>
> >>  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
> >>  headroom".
> >>
> >> 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:
> >>>
> >>> http://n8vem-sbc.pbworks.com/w/page/35158565/Build%20Instructions
> >>>
> >>>  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.
> >>>
> >>> http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder¶m=S-100%20b
> >>>  ackplane
> >>>
> >>> There is a new file for S-100  backplane fixes and improvements here:
> >>>
> >>> http://n8vem-sbc.pbworks.com/w/page/55620344/S-100%20backplane%20impro
> >>>  vements%20and%20fixes
> >>>
> >>> 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
> >> builders.
> >>>  Thanks and have a nice day!
> >>>
> >>> Andrew  Lynch
> >>
> >> -----
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> >
> 
>