Gregory's Serverone of today's pickups is this mystery Xebec RAM card. I can't find any information about it, so I think I'll try reverse engineering it.
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  the chip pins are crimped. this is a huge pain even with the super nice desoldering tool (FR-301) removed the one PROM chip and, confirmed, it was a pain. the other chips will be easier though... just clipping the leads of the chips using side cutters will make this much easier. they're just plain TTL anyway.   the sockets are going to be trickier. i'm thinking i need a soldering iron tip that can hit all the pins at once. did a web search and the 5th result was MY OWN DANG TWEET from like 2 years ago, lol. i think i just "Fooned" myself. @tubetime  @tubetime With as much de soldering that you do, I'm surprised you don't' already have one. routed (except for a few RAS and CAS lines). i also have the schematic, but it needs cleanup work. so this board looks like it does both XMS (extended memory) and EMS (expanded memory). expanded memory is banked and uses a 64K (iirc) window to access it. well crap, this board appears to be a clone of the Intel Above Board Plus 8 card. it sure looks the same! OK, here are the KiCad files. it's not really a fab-able design because there are still DRC errors, but at least the schematic is useful. @tubetime but has it ever been reverse engineered before…? That would be a bummer. But if not: success! @tubetime how do you go from PCB layout to schematic? When I did this, I ended up tracing the PCB in a CAD package, the writing a thing that analyzed the lines and spit out a netlist. I then learned that while many tools exist to convert schematics to netlists, I couldn’t find much to go the other way ‘round. @keelan i'm running a trace in layout, seeing where it goes, then creating the connectivity in the schematic and pushing it to layout to create the connection.  @tubetime RSVP all those legless chips. May their logic live on in the schematic, and in your future clones of their board! |
@tubetime There's no switches :o...