Solidisk flyer

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davidb
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Solidisk flyer

Postby davidb » Mon Oct 20, 2014 9:36 pm

I'm not sure if "flyer" is the right word. It's a single page advert, anyway, at a reduced size for forum disk space and browser memory reasons.

There's an interesting part for Electron users in the first section: "This unit (EFS) plugs into the PLUS-1 Expansion and allows connection of a twin disc drive system and a Winchester."

Later in the advert: "The unit is guaranteed for one full year but we warn the users that the built-in Sideways RAM is UNRELIABLE hence the reduced price of only: £50.00."
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flyer.jpg
Electron Disc Interface
Old Style SWR32 and 128K
Secondhand Refurbished Beebs
In Brief

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MartinB
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Re: Solidisk flyer

Postby MartinB » Mon Oct 20, 2014 9:52 pm

David wrote:Later in the advert: "The unit is guaranteed for one full year but we warn the users that the built-in Sideways RAM is UNRELIABLE hence the reduced price of only: £50.00."

:shock:

That's spooky David - have you by any chance been reading the thread about EUP, sideways ram corruptions and 'evil' Plus 1's? I think John (jms2) will be very interested to read that, it's certainly the first time I've seen Elk SWR corruptions mentioned when it doesn't cast aspersions on my hardware projects.... :lol: =D>

I shall link John over here.....

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jms2
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Re: Solidisk flyer

Postby jms2 » Mon Oct 20, 2014 10:25 pm

A remarkable thing to read in an advert for a commercial product! At least they are honest! :lol:

As Martin says, this is very interesting but would be even more so if we had access to a real example of this kit, which I'd imagine it's very unlikely. :(

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MartinB
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Re: Solidisk flyer

Postby MartinB » Mon Oct 20, 2014 10:31 pm

Hang on John, there's an address, you should write in and tell them.... :D

Oh, wait....

#-o

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jgharston
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Re: Solidisk flyer

Postby jgharston » Tue Oct 21, 2014 8:51 am

The second-hand BBCs are only guaranteed if you're a member of the Labour Party! (top righthand corner)

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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richardtoohey
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Re: Solidisk flyer

Postby richardtoohey » Tue Oct 21, 2014 8:54 am

jgharston wrote:The second-hand BBCs are only guaranteed if you're a member of the Labour Party! (top righthand corner)
:lol: What do Conservatives get? Master 128s? Lib-Dems - Electrons? Etc. Or just the BBC Bs but with no guarantee? :-k

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Re: Solidisk flyer

Postby daveejhitchins » Tue Oct 21, 2014 9:26 am

I'm surprised that Solidisk had problems with their on-board RAM. I can say with 100% certainty that our products didn't ever have a complaint about this issue. As the DFS filing system, on the Plus3/4 used RAM it would have become very obvious if there were any issues! Also, no reported issues with ABR and we sold a lot of those - probably over 10K, at least (OK, not all for use with an Electron system).

Dave H :D
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davidb
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Re: Solidisk flyer

Postby davidb » Tue Oct 21, 2014 9:35 am

MartinB: I remembered the EUP thread (and this discussion about Winchester disks) when I saw the advert, so I prioritised scanning it.

DaveH: Could it be that there were power supply issues? There are photos of the EFS cartridge at Chris's Acorns, by the way.

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daveejhitchins
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Re: Solidisk flyer

Postby daveejhitchins » Tue Oct 21, 2014 12:49 pm

davidb wrote:DaveH: Could it be that there were power supply issues? There are photos of the EFS cartridge at Chris's Acorns, by the way.
If they were power supply issues with the Elk then, probably, my products would have been affected as well? However, seeing the board, it could have been a problem with the 'tinned' edge connector - but, again, the Slogger products used the same finish on their boards and I don't recall hearing RAM problems there. Does anyone have a circuit diagram of the Solidisk unit? It 'may' be the design e.g. similar to MartinBs gating requirement! But, once more, that only seem to fix some of the affected units. Still more questions than answers . . .

Dave H :D

Edit: I've just looked at the flier again . . . That's a different unit, shown in the picture, than shown in Chris's Acorns??
Last edited by daveejhitchins on Tue Oct 21, 2014 3:03 pm, edited 1 time in total.
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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davidb
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Re: Solidisk flyer

Postby davidb » Tue Oct 21, 2014 1:49 pm

I'll try to post a close-up of the picture in the advert later today.

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jms2
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Re: Solidisk flyer

Postby jms2 » Tue Oct 21, 2014 3:07 pm

It's not possible to work out how the ram interfaces to the Electron based on the Chris' Acorns photos (as you'd expect). However, what I would say is that the board looks simpler than an AP3 - which suggests that maybe they used quite a simple method of connecting the ram.

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Re: Solidisk flyer

Postby DutchAcorn » Tue Oct 21, 2014 3:13 pm

daveejhitchins wrote:Edit: I've just looked at the flier again . . . That's a different unit, shown in the picture, than shown in Chris's Acorns??


I found another advert here that shows the same unit. It almost looks as though it only has one port instead of two. The photo shown with a review from A&B looks the same as the one from Chris's Acorns.

Paul
Paul

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1024MAK
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Re: Solidisk flyer

Postby 1024MAK » Tue Oct 21, 2014 3:25 pm

While you are all thinking about your theory's, one thing is a known factor - the edge connector. Any poor contact on an important circuit that goes via the edge connector, or is affected by another circuit that goes via the edge-connector can cause havoc with SRAM chips. You only need an extremely short break in the circuit and if the SRAM chips sees a valid write condition, garbage will be stored in whatever address is present on the address lines. Breaks on either the +5V or 0V/ ground will also cause corruption.

I have not done much in the way of testing on Elk systems, but I know of problems with Z80 CPU based systems that also use SRAM chips on expansion boards connected by edge-connectors. Also you will of no doubt heard of the ZX81 RAM pack wobble.

Keeping the PCB edge-connector contacts clean helps, but a good mechanical arrangement is also a factor. Remember, the proper way of using edge-connectors is as part of a card rack in a properly designed enclosure, where the cards are supported in runners (and some have front panels with retaining machine screws).

Myself, I have found that a slight movement or vibration can move a board just enough to cause problems.

Mark
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davidb
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Re: Solidisk flyer

Postby davidb » Tue Oct 21, 2014 7:00 pm

Here's the picture, though the one from Acorn Electron World probably shows as much detail as this does.
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Electron-Disc-Interface-picture.jpg
Electron Disc Interface

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daveejhitchins
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Re: Solidisk flyer

Postby daveejhitchins » Tue Oct 21, 2014 9:53 pm

Defiantly looks like just one socket on that unit . . . if it had two then I think you'd see it poking out over the back of the Plus 1.

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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