Atomwide A5000 8MB

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DutchAcorn
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Atomwide A5000 8MB

Post by DutchAcorn » Sun Jun 17, 2018 11:58 am

Got this expansion card with an A5000:
47019CC0-C227-43C8-9F73-19115E3FDAAE.jpeg
But it is partly populated and only provides a total of 4MB in this configuration. Google search comes up with Chris’ Acorns; a similar, also partly populated board.

Anyone here seen this board and are fully populated examples seen in the wild?
Paul

steve3000
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Re: Atomwide A5000 8MB

Post by steve3000 » Sun Jun 17, 2018 12:21 pm

I have one identical to that in my A5000 :)

It's provides an additional 2mb to the A5000, bringing it up to 4mb, the extra tracking would provide a further 4mb and dual MEMC sockets - and would plug into the MEMC socket on the A5000's pcb.

From my own investigations a few years back, I was confident in being able to source suitable RAM and MEMCs, but could not find a connecting block to plug into the original MEMC socket, and hadn't begun to investigate the two unknown ICs, which I suspect are probably custom PALs?

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Re: Atomwide A5000 8MB

Post by RobC » Mon Jun 18, 2018 11:43 am

You can get certain types of PLCC plug from RS (search Winslow PLCC - they're not cheap) but I've not been able to find a supplier for this type.

I suspect it should be possible to work out the PLD equations - there's a bit of relevant info here.

I've got a few A5000 8MB expansison but no working A5000 at the moment. They don't look too difficult to replicate.

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Re: Atomwide A5000 8MB

Post by DutchAcorn » Mon Jun 18, 2018 7:09 pm

RobC wrote:
Mon Jun 18, 2018 11:43 am
You can get certain types of PLCC plug from RS (search Winslow PLCC - they're not cheap) but I've not been able to find a supplier for this type.

I suspect it should be possible to work out the PLD equations - there's a bit of relevant info here.

I've got a few A5000 8MB expansison but no working A5000 at the moment. They don't look too difficult to replicate.
Interesting! But I found the memc is not socketed on my A5000 and there are still the two unidentified IC's...
Paul

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Re: Atomwide A5000 8MB

Post by RobC » Mon Jun 18, 2018 8:12 pm

DutchAcorn wrote:
Mon Jun 18, 2018 7:09 pm
But I found the memc is not socketed on my A5000 and there are still the two unidentified IC's...
I think it may only be socketed on the later Alpha/33MHz version. I'm pretty sure Steve is right and the unidentified ICs on the Atomwide board are PALs/GALs. So, it'll be a matter of tracing the signals going into them, working out their function and replicating their internal logic.

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DutchAcorn
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Re: Atomwide A5000 8MB

Post by DutchAcorn » Mon Jun 18, 2018 8:32 pm

RobC wrote:
Mon Jun 18, 2018 8:12 pm
I think it may only be socketed on the later Alpha/33MHz version.
The Alpha/33 version was launched in 1993 and this board is from 1991? Odd.
Paul

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Re: Atomwide A5000 8MB

Post by matt_nottm » Mon Jun 18, 2018 8:39 pm

Does this help explain?

"Fitting the 4Mb upgrade is a simple task involving no soldering or expert
knowledge. The 4 to 8Mb upgrade however, requires the A5000 to be sent
to Atomwide for fitting. Courier collection & delivery of your machine is
therefore included in the price.

4Mb RAM card - £110.00 (ex. VAT) 4 to 8Mb RAM - £399.00 (ex VAT)"

Acorn User May 1992

steve3000
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Re: Atomwide A5000 8MB

Post by steve3000 » Mon Jun 18, 2018 10:47 pm

As above, the upgrade needed the original A5000 pcb to be modified. I once owned an original A5000 that had been modified to take a simtech 4-8mb upgrade, the pcb modifications were probably similar to what the Atomwide board needs: the obvious socket fitted for the MEMC, then the two large axial capacitors either side of the MEMC to be moved to the underside of the pcb, and one nearby surface mount capacitor to be removed (later two modifications were to provide space for the upgrade pcb and its stands, so might not be required for the Atomwide board).

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Re: Atomwide A5000 8MB

Post by DutchAcorn » Tue Jun 19, 2018 5:19 am

matt_nottm wrote:
Mon Jun 18, 2018 8:39 pm
Does this help explain?
Yes it does!

steve3000 wrote:
Mon Jun 18, 2018 10:47 pm
the pcb modifications were probably similar to what the Atomwide board needs: the obvious socket fitted for the MEMC, then the two large axial capacitors either side of the MEMC to be moved to the underside of the pcb, and one nearby surface mount capacitor to be removed (later two modifications were to provide space for the upgrade pcb and its stands, so might not be required for the Atomwide board).
The Atomwide board design leaves enough space for the capacitors but it seems the plug on the memory board needs long pins to reach the memc socket.

5798B627-BB1E-4A2C-9650-908F47271EFC.jpeg
63F4A81E-E6B0-40A1-AD40-C6156773C799.jpeg
Paul

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Re: Atomwide A5000 8MB

Post by RobC » Wed Jun 27, 2018 8:24 pm

Had a look through my A5000 8MB expansions. Two are by Simtec and the other is by Atomwide but not the one shown in this thread.

However, it does have two GALs fitted - it's possible that they are similar to those intended for this card.

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Re: Atomwide A5000 8MB

Post by lcww1 » Wed Jun 27, 2018 9:04 pm

I think that the 8Mb RAM card in one of my A5000s is a fully populated version of the Atomwide card shown in the picture at the beginning of this thread. I’ll need to dig out the machine from under the rubble of electronics clobber on my desk and take a picture. It would be marvellous to clone this RAM board, so that A5000s could be more readily upgraded.

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