www.jupiter-ace.co.uk

News & Hardware Index > Memotech Keyboard


Memotech Keyboard
T
he Jupiter Ace's keyboard is a 40 key rubber membrane, with auto-repeat on every key, and two shift keys allow ASCII codes to be produced. The keys have a rubber conductive contact set into each key. When pressed it would short the pcb contacts allowing the electrical signal to be decoded into the character that the user has typed. The most famous rubber keyboard membrane computer is the ZX Spectrum of which the Ace's can be considered a similar type but not as responsive.

The Ace's keyboard was very poor and difficult to use for a few hours at a time many users began to devise their own ways of adding a full size proper keyboard [see CN Customised Ace]. The Ace was not around long enough in the market place unlike the ZX Spectrum which had a number of manufactures producing add-on keyboards. But one company did build a full size, well built, proper keyboard, Memotech Ltd. The keyboard was basically the ZX81 Memotech keyboard modified for use with the Ace. It has a keyboard buffer interface that needs to be fitted to the Ace's expansion port with an adaptor. The buffer interfaces signals are in the order of the ZX81's expansion port. The adaptor changes the format of the signals to the order of the Ace's expansion port, see the Motherboard Expansion Card or the Trumpcard Card for more details on how to make ZX81 peripherals work with the Ace. or the. From this keyboard buffer was a small ribbon cable which fed into the Memotech keyboard. It may have been possible to use both keyboards at the same time!

The keyboard keys have blank key tops so two sheets of self adhesive labels were supplied also a new front panel trim. The labels were printed on a very sticky matte black material, which blended with the key tops. The instruction sheet for the keyboard, with a scan of the front trim can be downloaded here (Hi Res Tiff files).

We have never seen any adverts for the keyboard, and they very rarely come up for sale on internet auction sites. We do have a few images below, we have also taken some images of the ZX81 version to show how it was built. If you can help us out with some images of one of these Jupiter Ace Memotech keyboards then please send in your images.
The Jupiter Ace front trim for the keyboard body
The Jupiter Ace front trim for the keyboard body.

The instructions sheet from Boldfield Computing
The instructions sheet from Boldfield Computing.
 Jupiter Ace Memotech Keyboard and Buffer
Note the Jupiter Ace logo on the keyboard front.


The buffer IC is a 74LS244.


Note how the keyboards PCB has been rewired and tracks cut, this is why we are sure its a ZX81 version that has been modified.
  
Take a look at these two images, one has black keys and the other white, yet you can make out the Jupiter Ace logo on the front of the keyboards. Could one be a prototype?


These images below have been taken for a ZX81 Memotech keyboard to show you the build quality, we no reason to believe that the Aces version would be any different.
Case   space filler

both together fit like this.