Envelope-to: craig@sbc-85.com
Delivery-date: Mon, 06 Mar 2023 08:20:45 -0600
Subject: Re: 8 slot SBC-85 backplane
To: craig@sbc-85.com
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From: denverh <denverh2000@gmail.com>
Message-ID: <00998c72-d6bd-5e22-6da0-5ec45f9d7d54@gmail.com>
Date: Mon, 6 Mar 2023 08:20:32 -0600
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craig@sbc-85.com wrote:
> Hi Denver, thanks for the notice on your hackaday.... I am very impressed.  I would like to get the word out about your project, maybe do a short video on your efforts once I get it going on my setup.  It is hard to believe, but it seems not everyone is infatuated with magnetic bubbles.   I know that I have sold a few dozen bubble boards and there are a number of others that downloaded and built boards for themselves.  However, based on the number of questions I get on the bubble board, I think it is a small pool of people that are playing with it or have it going.  I will directly email some of them a link to your hackaday writeup and see where it goes.
You're right, the allure of MBMs doesn't seem to make much of an 
impression on most people.  So yes, spread the word.
>
> Whenever I play with the SBC-85 I am always having to swap out boards, so I am thinking that I should make a larger backplane for the SBC-85, something more like the STD-85... 8 slots.  I need to figure out how to do card guides, since I ran components very near the edge and on some boards, like the bus monitor, brought things out the left edge for convenience or to make them more visible.
I know.  Four slots seems like it should be enough, but if you have a 
CPU, I/O, Memory, and MBM, then it's full.  And that's a fairly minimal 
system.

With more slots, a single 5V supply might be less practical.  I was 
toying with the idea of making a holder or base for the backplane that 
incorporated a power supply that used a higher voltage as input.  
Perhaps 12V to 15V.
>
> the CPU, serial/parallel I/O card both have connectors out the left side, the bus monitor switches and LEDs on the left and also the right, cassette tape interface out the left.  the rest of the cards are fairly well behaved.   also there are three different heights for the cards.
>
> any thoughts about this?
That's a tough one.  The RC2014 boards all have a hole on one side for 
spacers, but I don't think I've ever seen them actually used. Looking at 
the SBC boards that I have, only the right hand edge is consistent, but 
there are also components close to that edge.  All I can think of right 
now would be some kind of clip or spacer that attaches to the boards, 
rather than an actual fixed edge guide attached to the backplane.  Or 
maybe something that would directly support the solder side and have 
some kind of mechanism that would operate on the component side.
>
> Again, fantastic effort on FDOS, TEA, and all the support.
Thanks, it's been lots of fun working with 8 bit systems again.

Thanks,

Denver