Does anyone have a 6 slice backplane(s) for RISCPC?

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Paul
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Does anyone have a 6 slice backplane(s) for RISCPC?

Post by Paul » Thu Nov 03, 2016 8:51 pm

Hi everyone!

I'm progressing my "Acorns in Broadcast Television" restoration project and are in need of one (or a couple if possible) of the 6 slice backplanes..

Could anyone help / sell?

Cheers,

Paul.

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IanS
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by IanS » Sat Nov 05, 2016 3:49 pm

I have an 8 slot you could cut down (yes, they did have a "cut here" printed on the board).

What setup needed 6 podules?

Paul
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by Paul » Fri Nov 11, 2016 9:20 am

IanS wrote:I have an 8 slot you could cut down (yes, they did have a "cut here" printed on the board).
I've sent you over a PM - that would be amazingly helpful! Thank you.
IanS wrote:What setup needed 6 podules?
So, I'm in the process of conserving and rebuilding a RiscPC that was actually used to provide graphics for shows on the BBC. Sadly, many of the machines were affected by battery corrosion, including quite bad corrosion across the 6 slice backplane. Interestingly, I'd noticed the cut line on the backplane used by the BBC's computer! It would be interesting to try as it is first before cutting. I do know the 8 podules can fail in certain setups however, so a cut may be necessary.

So what were the 6 podules needed for? machines were used on multiple jobs (or TV programmes), and they required different cards, so some machines were 'reconfigured' with hardware, but one of the machines actually had all the cards installed for development of shows. I'm looking to build up the machines in this format so they can demonstrate all of the content created.

The podules used in the same machine were:

SLICE 1:
1/2. Millipede Alpha Lock Genlock card (this only uses one electrical connection, but two physical podule spaces)

SLICE 2:
1. Millipede Prisma 3 Podule
2. Dual Serial Podule

SLICE 3:
5. Acorn MIDI Podule
6. Millipede APEX Graphics Podule.


So, if I can get it working as an 8 Podule backplane reliably, I'd ideally add:

SLICE 4:
7: Simtec USB / IDE / Ethernet card.

Cheers,

Paul.

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IanS
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by IanS » Fri Nov 11, 2016 4:30 pm

Before I post the board to Paul, this is what the board looks like.
PICT4676.JPG
PICT4674.JPG

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daveejhitchins
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by daveejhitchins » Fri Nov 11, 2016 4:37 pm

Don't you need to move the terminating resistors, from the top pair to the next pair down, when you cut the backplane down for a 3 slice machine?

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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IanS
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by IanS » Fri Nov 11, 2016 4:40 pm

daveejhitchins wrote:Don't you need to move the terminating resistors, from the top pair to the next pair down, when you cut the backplane down for a 3 slice machine?
Probably, I'll leave that to Paul to do if he decides to cut it.

Paul
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by Paul » Sat Nov 12, 2016 9:24 pm

I'll try it as is first, (I try to avoid cutting!).

But if it doesn't work then I'll cut it when I'm sure I've got it all figured out!

Paul.

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daveejhitchins
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Re: Does anyone have a 6 slice backplane(s) for RISCPC?

Post by daveejhitchins » Sat Nov 12, 2016 9:29 pm

The problem with these huge backplanes could be not enough decoupling! It may be worth adding several low ESR Tantalums and some SM 100n ceramic caps - if you have any problems. With limited production, maybe they didn't debug it fully?

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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