I own only one of these modules. It´s a 256K L2 cache module with integrated buffer circuits and a proprietary pinout.

To make things worse, FIC sold two different versions with different pinouts (and the same "VLB"-socket). Only the one in the pictures works on a 486-GAC2 and a few other FIC mainboards.

When you add the cache module, the 3.3V VRM module and a AMD 5x86 the performance is quite impressive compared to the original configuration.

Wow, ok, didn't expect someone to actually have one. Thanks for sharing.

So, at least it is clear that there is nothing proprietary about the chips used, some ram & buffers, so that's good news I suppose.

One day maybe my ebay saved search will ping something, not that it has for some years now 🤣

As difficult as the task may be, I have started to map the traces from the pictures you provided, at least those that don't end somewhere under a chip.

@majestyk
Would you be able to take a few more pictures, some sightly angled maybe, to make the shadowed areas clearer?
And do you have a multimeter?
Once I've mapped everything I am able to, it would be greatly beneficial if you could confirm my findings, and help map the traces that are under the chips.
I've discussed this with my electronics expert friend, and he doesn't see any reason a repro can't be made, with some effort.

I will take some more detailed pictures.
I could also could do some measuring to identify the ground and Vcc pins and check for continuity between all the I/O, address, CS, CE pins at each SRAM and buffer chip and the pins of the "VLB"-socket.
This will probably not reveal all the information like the number of layers, or traces that connect chips with each other.

majestyk, did you manage to find a moment to look into this further?

I´m on a holiday currently and wasn´t sure if you were going to persue this further. I will provide the details as soon as I´m back home!

Hey guys i would gladly pay for one of these if you guys end up making them. Best of luck

I have a feeling you will need to attack it from both directions. Take out the mobo and map this slot pinout to chipset.
next find another board with same chipset and onboard cache sockets https://theretroweb.com/motherboards/?chipset … 85&showImages=1 to complete the map
chipset datasheet pinout page 30
https://datasheet.datasheetarchive.com/origin … DSA00204677.pdf
https://dosdays.co.uk/media/via/VIA_82C496G.pdf

I added two pictures above after cleaning the stick.

rasz_pl, do VT82C486A and VT82C496G share the same pinout?

I have most of the FIC mainboards with this chipset here, so I could do the measuring. The two 244 buffer chips are on the cache-stick here - we need to measure between the chipset and the buffer inputs in this case.

If the L2 cache stick is present and you do a few little mods, you can run an AMD 5x86 @133 MHz in L1 cache Write Back mode. And that´s quite a progress for a mainboard that was usually equipped with a SX33 CPU...

majestyk wrote on 2023-09-14, 14:07:

rasz_pl, do VT82C486A and VT82C496G share the same pinout?

I didnt spot the number difference when searching and "helpful" google decided to ignore quotations marks 🙁. NVM then 😀