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BlackMagicalBus™ for Memory/PDS Subassembly of reduced footprint LCIII in Classic Project, etc.

Trash80toHP_Mini

NIGHT STALKER
Roots or this craziness to be found in the MagicalBus thread for the budding LCIII in SE project. PDS dungeon breakout required fot that one, but it's only a one way street. Inspiration for that was Radius' fabulous Magic Bus implemented as an adapter card for what was built into their SE Accelerators.

LCIII in Classic poses a brand new problem so I've moved on from PCI Connector to the much tighter pitch, 240 pin DDR2 Memory Module as the LCIII Memory/PDS Subsystem interface which will be running 120 connections up one side of a tall format take on the DDR2 DIMM and back down the other 120 teeth on the edgecard connector..

Was figuring that a notch on one side and a bit of an arc on the other and angled insertion and removal would work:

1647990279297.jpeg

But KISS principle violation forced me to break out of the Symmetry/Parallelism box constraint. Once outside the box, it pretty much fell into place.

BlackMagicalBus-Concept-00.JPG

BlackMagicalBus-Concept-01.JPG

Once upon a time, by doing the same thing I came up with the suggestion for fitting something similar on a 10cm Square PCB. 😉

Note the band of Surface Mount Memory on the board as above, the Unit will look much like this 72pin SIMM expander:

Classic_III_Memory_Riser-01.JPG

Surface mount pad real state available for banks of memory on both sides of the riser available under SIMM, VRAM and ROM connectors, per
@max1zzz suggestion.

At any rate, @k24a1 suggested a Compact III project, and here a bit of it lands with a thump.

 

Trash80toHP_Mini

NIGHT STALKER
Part II: post was too long, too many pics it would seem: diagrams

DDR2-BlackMagilBus-PCB _Egecard_Spec.JPG

DDR2-BlackMagilBus-Connector_Spec.JPG

Dimm Slot is a much more rigid interface than the MagicalBus PCI /slot/Card proposed in the earlier thread and locked in as well. On the forward side the extractor should be fine I think, but the ear of the backside extractor latch may need to be filed down a bit, if overhead is too limited, but would still remain fully functional I think.

Well there it is @max1zzz whatcha thinking?
 
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