Memory Packs

[David G]

back to: Index of RAM packs

LOW RECTANGLE shape case

SPECIAL RAMPACK by audio computers of Essex, England



Sinclair User April 1982 Issue No 1 page 56

Audio Computing has the largest memory pack available, 128K of RAM but only 32K of it available at any time. To switch between sets of
32K, called banks of memory, a manual switch has to be thrown and the ZX-81 has to be re-set to start up the Basic system again. That is not
very convenient, as it cannot yet be operated from software or the variables transferred from bank to bank.

detailed photos


Photo and Instruction Sheet

board marked 'SOLIDISK ltd'

[David G]

WIDE LOW RECTANGLE
* with case industrial design of the not-as-wide SPECIAL RAMPACK

STL MICROPERIPHERALS - MADE IN ENGLAND

Photo details: ordi5

With what looks like an EPROM socket. Some, but not all, units have an On/off switch and buzzer

Eight ET 4116N-3/HS 8320 datecode DRAM chips (total 16KB)

[David G]

I guess we should talk about the ZX80 RAM PACKS, in case you run across one. Looks like the same connector as the ZX81. Do they work with the ZX81?

* sinclair ZX80 1-3K BYTE RAM PACK
* sinclair ZX80 16K BYTE RAM PACK [black]
* MaFli 1-3K DIY clone


Also see

• Rick Dickinson photo gallery

• bing image search

• ZX80 3K Ram Pack memory

• giannopk add-on 2K RAM pack

• 3K schematic

sinclair ZX80 1-3K BYTE RAM PACK
has a 1970s look about it

is populated with 1, 2, or 3KB of memory

Sinclair
ZX80 RAM PACK
MADE IN ENGLAND

with plastic rivets

The Ram pack is powered from the stabilised 5v obtained from the ZX80...the supply current is approximately 70, 130 and 190 mA

[David G]

Jigsaw was by Gladstone Electronics of New York, who sold the RAM pack first under the name Gladstone 16K RAM, later Jigsaw 16K. It seems to be related to Data-assette, perhaps they resold them or were the original manufacturer?

Jigsaw use the board labeled "BYG BYTE" as seen in the previous post


In England there was a RAM Pack which was also advertised by:
Phoenix Marketing,
Oaklands House Solartron Road,
Farnborough, Hants. Tel:(0252) 514990

* Byg Byte 16K Ram Pack
* Byger Byte 32K+ Ram Pack (with pluggable back)
* Standard 32K Ram Pack
* 64K Ram Pack

I haven't been able to find pictures of these packs, but that product lineup matched the Gladstone lineup

[David G]

Anyone seen this brand before? It is currently on eBay

DOWNSWAY
16K RAM PACK
square case, seems thicker than the Sinclair unit. Back of case has no writing

[Moggy]

Downsway Electronic Ltd were/are based in Surrey UK and as well as this pack they made a 64k version for the 81 plus a 48k pack for the Jupiter Ace (Pictured below) as well as a programmable joystick interface for the ZX Spectrum. (see videos)

Their products were sold by Data-assette in the US.

https://www.youtube.com/watch?v=cbH6HF0it1s

https://www.youtube.com/watch?v=nUHI7eA7j4k

[David G]

Thanks, Moggy!

Hmm, that 48K pack uses 4416 RAM. But why are there only six RAM chips? ... searching ... they are 16K by 4-bit, so a pair is 16K. Interesting

[1024MAK]

Four bit DRAM chips became more popular as the price of DRAM fell. They turn up on 8 bit computer main boards later on as well (for example the 256K bit 64K x 4 bit type used in Amstrad made +2A/+2B/+3 and Acorn BBC Master).

Mark