Home made memory expansion.

[Feek]

I went to my mums today and picked up an old computer of mine.

In it is a home built memory expansion card. It's a thing of beauty.

The front is just four chips in sockets, the back is where it all happens.

Take a look at this.

http://ocukroguesgallery.com/feek/temp/memory-20110203-213708.jpg

I built that. From scratch. I had a circuit diagram for it and just built from the circuit, if I remember correctly the three memory bugs are effectively paralleled up with some switching lines going up via a controller to the BUS connector.

Total capacity - 24Kb RAM.

Here it is fitted in the computer.

http://ocukroguesgallery.com/feek/temp/interior-20110203-213909.jpg

Even back then I was overclocking. There's a switch hanging out of the back which doubles the clock speed from 1MHz to 2MHz!

Those were the days, huh? Can you imagine building a memory expansion card for a computer nowadays.

[Will]

*like*

[Mondo]

Whoa, i never knew you can do that kind of things DIY!

[Feek]

Whoa, i never knew you can do that kind of things DIY!

I doubt you can now - That was back in the very early 1980s.

[Mark]

No way you could do this now (most computer PCBs are multi-layer due to the sheer number of tracks required), but I do remember when things were much simpler and you could do this sort of thing.

Never built one myself but I know of others who did. It's now that far from the time you could get an entire computer in kit form. Imagine doing that now!

Sadly my knowledge doesn't extend to recognising the computer involved, but credit for doing it nonetheless. :)

[kaiowas]

Back in the day when "Building your own computer" meant something!

I like the "Side two" printing on the board too, really dates it back to the age of vinyl.

[Feek]

It's actually an Acorn Atom from around 1980 and it's going on eBay on Sunday.

[Nutcase]

Do I get points for recognising an Acorn product? :evil:

When we were using the Beebs all the time we bought all sorts of kits you assemble to upgrade them. Don't think we ever made anything from scratch though!

[Mark]

I suspected it might have been but wasn't sure.

Grandparents had an Acorn Atom. I think it got fried during a thunderstorm, otherwise it'd probably still be there.

[Jonny69]

Back in the day when "Building your own computer" meant something!

I like the "Side two" printing on the board too, really dates it back to the age of vinyl.
Amen to that. Only the other day I was talking to some friends about how the days of being able to start certain businesses are over. One example was creating an empire based on a computer built out of bits from Tandy :D

[Feek]

http://cgi.ebay.co.uk/Acorn-Atom-fully-expanded-extra-RAM-and-ROM-boards-NR-/160542463401?pt=UK_VintageComputing_RL&hash=item25611395a9#ht_6911wt_922

No bids yet but plenty of watchers.

I'm going to try and slap a PSU up it this evening and see if I can show it working.

[Feek]

It works!

http://ocukroguesgallery.com/feek/temp/working-atom-01-20110208-182737.jpg

[Mark]

My bad - t'wasn't an Acorn Atom - it was an Electron. My dad used a BBC Model B for RTTY, and he was near Chelmsford at the time, so you never know. :)

Hope it sells. I recently had to bin a 20-year-old computer as there was no other way I could get rid of it. :(

[Nutcase]

Awesome :D

We've still got 2 BBC B's, a Master and get this - a 20mb hard drive :D

[Feek]

Very disappointed it only sold for £90 considering the last couple I saw on eBay went for £155 and £26.