Making it pretty
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PeorMejor 
Viernes, 21 de Diciembre de 2007 00:00

But perharps not usefull for everybody, as space is very limited on the Spectrum case. Event worse if we consider the rubber key model case. Anyway, if you have a Plus cabinet, or better, a DKTronics keyboard, please, read on.

As you can see, we have a bank of eight memory chips. Normally the 4116 DRAM chips are soldered without sockets. This picture belongs to my all-socketed Spectrum.

The idea is to build a PCB, using molded pins to carry signals and power from the Spectrum PCB to the adapter PCB. This way, you can simply plug-in the adapter (or solder it to the Spectrum PCB) to make it work.

The PCB is very simple, as it doesn't require any components apart from the SIMM socket itself. This is the layout, suitable for one-side PCB:

DOWNLOADS

A single ZIP file with two PCB versions (600ppp): with ground plane and without it. Depeding on the PCB etching method, you can need one or another. Also included a wiring diagram, with the two wires you have to add, in red, and a picture of how to fit the adapter to the Spectrum PCB.

 
Comments (2)
TMS44C256DJ
2 Miércoles, 31 de Marzo de 2010 07:09
Ratos
Daniel, I would apreciate if you can send me diagrams and pictures of your adapter.
I managed to find a bunch of TMS44c256DJ and I want to use these instead of damaged 8x4116 inside my spectrum. And please, explain me what to do with the OE (data output enable) pin of 44c256. This pin is not present on SIMM30. Thank you in advance.
Another alternative
1 Martes, 01 de Septiembre de 2009 22:43
Daniel
Hello,

I have made a similar board for using 2 x 44100 chips (256K x 4 bits) that are the most common memory chips of the 386..586 era and very easy to find them. The main advantage of my design is that if fits inside a normal Spectrum case. If you wish I can send you the pictures and diagrams

Regards,

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