[N8VEM: 19848] Altair 8800 Motherboard Replacement

[Kip Koon]

Hi Guys,

I have an Altair 8800 full of cards, but the backplane is in 3 4-slot
sections wired together.

Does N8VEM have any motherboards that will fit my Altair should I choose to
restore it? It has not been powered up since before I bought it way back in
the late '70s to early '80s timeframe. I looked to see if I could easily
disconnect everything from the power supply several years back and I found
that the front panel is permanently wired to the backplane so if I do
replace the backplane I have a lot of work ahead of me. Total restoration
could take a while and my workbench is kind of dinky so leaving everything
laid out is not an option at this point. I know there is at least a 21 slot
S-100 backplane, but from what I remember looking inside my Altair, I
wouldn't think that would fit.

What procedures should I follow should I decide to dive into this project?
I would like to see it run someday though I imagine it would be painfully
slow compared to my 25MHZ Z80 Multicomp running MP/M with 512KB of ram.

Any thoughts, ideas, helpful hints?



Kip Koon

<mailto:***@sc.rr.com> ***@sc.rr.com

<http://www.cocopedia.com/wiki/index.php/Kip_Koon>
http://www.cocopedia.com/wiki/index.php/Kip_Koon

[jdavis]

Post by Kip Koon
Hi Guys,
I have an Altair 8800 full of cards, but the backplane is in 3 4-slot
sections wired together.
Does N8VEM have any motherboards that will fit my Altair should I choose
to restore it? [...]

Any thoughts, ideas, helpful hints?
Hmm, does the 3 piece motherboard have any problems? That setup was period
correct, taking out the motherboard for a more "modern" one seems like a
shame, like taking out the original iron block engine from a classic car
and putting in a modern aluminum block engine. Unless the motherboard and
cards are damaged (corrosion, mice) I'd be tempted to restore it with
original parts. The vintage computer forum at
http://www.vintage-computer.com/vcforum/forumdisplay.php?24-S-100 is a
helpful resource, in fact there's a long thread there where someone is
restoring an Altair 8800.

That said, building a N8VEM S-100 system would be very helpful since you'd
have known-good (once they're built and tested) parts to check the 8800
with.

[Kip Koon]

Hi jdavis,

In that spirit then and for the sake of completeness, do you think it would be ok to wire in another 4-slot backplane until it was full?



Kip Koon

***@sc.rr.com

http://www.cocopedia.com/wiki/index.php/Kip_Koon





From: ***@googlegroups.com [mailto:***@googlegroups.com] On Behalf Of jdavis
Sent: Monday, July 13, 2015 5:39 PM
To: ***@googlegroups.com
Subject: [N8VEM: 19851] Re: Altair 8800 Motherboard Replacement




On Monday, July 13, 2015 at 9:34:20 AM UTC-7, computerdoc wrote:

Hi Guys,

I have an Altair 8800 full of cards, but the backplane is in 3 4-slot sections wired together.

Does N8VEM have any motherboards that will fit my Altair should I choose to restore it? [...]

Any thoughts, ideas, helpful hints?





Hmm, does the 3 piece motherboard have any problems? That setup was period correct, taking out the motherboard for a more "modern" one seems like a shame, like taking out the original iron block engine from a classic car and putting in a modern aluminum block engine. Unless the motherboard and cards are damaged (corrosion, mice) I'd be tempted to restore it with original parts. The vintage computer forum at http://www.vintage-computer.com/vcforum/forumdisplay.php?24-S-100 is a helpful resource, in fact there's a long thread there where someone is restoring an Altair 8800.



That said, building a N8VEM S-100 system would be very helpful since you'd have known-good (once they're built and tested) parts to check the 8800 with.
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[G. Beat]

There is a separate N8VEM group for S-100 computers (Google).

The S100 Computers web page documents the S-100 Bus and historical boards that were offered.
http://www.s100computers.com

S-100 Box and Card Cage
http://www.s100computers.com/My%20System%20Pages/The%20Box/The%20Box.htm

Under its New Boards category -- documents PC been that have been offered by this interest group.
http://www.s100computers.com/My%20System%20Index%20Page.htm

S-100 Boards For Sale
http://www.s100computers.com/Cards%20For%20Sale.htm

Grant Stockly's Altair Kit project (2006/2007) duplicated the original Altair method of 4-slot additions to the motherboard.
http://www.altairkit.com

John Woodall, eBay seller: vintagemicros has offered S-100 motherboards in the past.
http://www.ebay.com/usr/vintagemicros