If anyone can confirm that theirs is a 1MB cache, it would be great if you could upload a scan labelled as such to the
Nubus Mafia. I am pondering the possibility of hacking 256MB SIMMs into 1MB SIMMs, and I want to have a closer look at the similarities and differences.
I have a 1MB cache somewhere. I don't know if I can lay my hands on it. It was from NewerTechnology. I bought it as a clearance item from some Mac equipment seller, years ago, turned out it was defective, and NewerTech replaced it. The original, defective one had a bunch of chips on board. The replacement clearly used higher capacity chips and fewer of them. So the original defective one would have been similar to what you're trying to do probably--build up smaller chips into a larger agglomerate.
One thing I do have which might be helpful for you is the pinout for the cache slot--sort of. As you may know, the cache slot and the ROM slot in the x100 machines are interchangeable, i.e. the ROM and Cache DIMMs may be installed in either slot without preference (except it's sometimes good to put the cache closer to the CPU). What you probably do not know is that the pinout of the ROM slot is the same as on the x500 series and on the Beige G3 series, with some minor differences. And I do have most of the pinout for the Beige G3 ROM slot. If you want it, email me at
trag@io.com and I'll throw it up on the space I use for public files.
One difference is that the Beige uses pins, which are unused on the x500/x100, for the 3.3V supply, because its parts run on 3.3V whereas the older machines use chips which run on 5V.
It would still be a good idea to confirm the pinout but this will get you way more started than probing at random. I only identified the pinout needed for a ROM module. There may be other pins implemented in a cache module. Wouldn't there be something like a cache hit/cache miss signal back to the host?
BTW, OWC has bundles of those 256K caches for really low prices.