Strange DKTronics 64K expansion.

[Bryce]

I was sent this picture of a DK 64K expansion lately. It's neither the original 8 chip RAM version, nor the later SMD version. It's somewhere in between. The strange thing is that all the logic ICs are in place, including the two needed for the 256K conversion, but it uses two 4464 (64K x 4bit) ICs, which are even in sockets, but there was never a 256K x 4bit IC that would have fit there. This version isn't mentioned anywhere in the Wiki or in the Galery, so I'll upload it there. Does anyone else have this version, or further information about it?

Bryce.

[Gryzor]

Did it come in a case?

[Bryce]

I think so, but I've on seen a picture of the PCB (the one above).

Bryce.

[Gryzor]

Are we sure it's a production model then?

[Badstarr]

Strange if there was no IC available ? Maybe it's a prototype and they were just plugging parts together that would work for 64k but knowing that some modification whould be needed for 256k? Or close to the end of a products life cycle (from my experience with cars etc) they were just using up their stock of parts. An example (car example) would be the drop links on of the stabliser bar on my car were actually not supposed to be fitted but they are compatible albeit with a smaller bolt fitting which means to replace them with the specified part the hole the bolt passes through has to be made bigger. It turns out that the parts I'm talking about were supposed to be fitted to a Nissan Cherry, the design being very similar to the Sunny. I've witnessed this sort of thing many times at work too.

[MacDeath]

is it working ?

[Bryce]

It works and was built in late 1986 or early 1987, so it's not a prototype and really was produced at some time between the original 8 chip version and the SMD version.

Bryce.

[zhulien]

I actually had my expansions before made by a guy here in Melbourne in the late 80s.  He claimed to have rights to manufacture there in Australia and basically had the board designs and official casings - he used whatever chips he had available at the time, so it could be from a similar outfit?

[Gryzor]

Huh, interesting tidbit. A single guy having the rights to manufacture for the territory?

[buzby]

bryce thanks for making a thread about my 64k expansion

gryzor it comes in the original dktronics 64k expansion case and works fine, ive had this about 2 years of which i purchased of ebay the advert just said 64k dktronics expansion for the 464 and the 6128.... i know you cant use this model on the 6128 but i might give it ago with it been different and report back once i have an answer

bryce if you need any more pictures i will email them to you ie: the case and the back of the circit board etc... please let me know

[Bryce]

Some more pictures might be nice for the Gallery, but I don't need any more pictures. The schematic seems to be the standard DK schematic for 64K, just using  different RAM ICs.

Bryce.