Sinclair ZX80 / ZX81 / Z88 Forums

Hey this is neat. I wish they still had stores like this


The Maplin Extendiboard GBO8J, a 3-slot extender for the ZX81


In 1982 it was £13.95 for the board and 4 edge connectors, though some people got by with only two connectors and added more later ...


Parts Prices from Electronics THE MAPLIN MAGAZINE September-November 1982 Vol. 1 No. 4

page 58

a mother board is available the ZX81 (GBO8J) and will accept the Sinclair 16k RAM pack and up to three plug-in modules. You will need four PC edge connectors 2 x 23 way (RK35Q) and the pcb

page 47

GBO8J ZX81 Extendiboard Price £3.95
RK35Q P.C. Edgecon 2 x 23 way Price £2.25

See also this post

Yes, it’s a shame that Maplin (the original company) went into administration and closed. A new company bought the brand name and opened up as an on-line shop. But they don’t sell kits or indeed electric components.

I spent many an hour browsing through the Maplin catalog (that was available in WH Smith’s, a high street newsagents and book store). Then later, in their shops (they opened one in Bristol, eventually they had three in the Bristol area) and on their web site.

Mark

Was a big part of my life in my early 20's at college, even bought a couple of the cover art posters. Wish I still had them, but they did not survive the repeated moves from one digs to another

The Mapin shop in Nottingham was good but parking was a nightmare. The later shop that opened in Mansfield was great, but by then the electronic components were pushed to a little store room at the back. Their Ni-Cad batteries were the bargain of the century though. Still have a few left.

I have one of those little extender boards somewhere. As for Maplins, whilst they were convenient they were a bit pricey.
I used to go to a Mondo Maplin which meant they should have at least one of everything in the catalogue but it was never the case.
I do remember getting a nice trio of American Eminence speakers for the stage amps I was building for myself and being able to buy components in small quantities was useful I found.

Like Redgatemodels experience, the Maplin store I used ended up with an ever decreasing components stock and became a glorified version of Toys are us where it was easier to buy a remote controlled helicopter than a bag of resistors.
In the end I used Farnell whose HQ was just up the road, had a thousand of everything plus it had a trade counter now sadly defunct with mail order being the current way of purchasing things.

thanks to everyone for the comments

I saw a reference to this board, but not much detailed information on it. Now I'm understanding how y'all used this part, like this photo from Mark with I/O cards

1024MAK wrote: ↑Sat Nov 30, 2024 11:16 am See also this post

1024MAK wrote: ↑Tue Aug 01, 2017 9:53 am I also have the Maplin extension board. That's what my GA90X plugs into (it having a "male card edge" rather than it's own female socket).

Maybe a picture will demonstrate what I mean more clearly...

And thanks to siggi. "backplane" was the term I was trying to think of. Maplin called it a "motherboard" in the magazine, but backplane is more descriptive of its function

siggi wrote: ↑Mon Aug 07, 2017 10:09 am Torsten made a new backplane similar to the Maplin board

With all this hardware, it's as if the ZX81 could run a nuclear power station!

Just saw this old project from kmurta using what looks like an Extendiboard. Is that a flexible board-to-ZX81 connector? I would think using a ribbon cable might eliminate connector wobble issues


Since none of these boards are available any longer, what is the current go-to for a hobbyist slot extender board?


JOY81 - Programmable Joystick Interface

ZeXtender prototype, an extender board similar to the Maplin Extender


Then PokeMon mentioned his "smaller" extender board. This is the no-longer-available ZX81XT extender board for developers

David G wrote: ↑Thu Dec 12, 2024 11:07 pm Since none of these boards are available any longer, what is the current go-to for a hobbyist slot extender board?

Check the David Stephenson's ZX81 Bus Extender.