[Coladam] Memory expander
gimechip at live.com
Wed Aug 1 08:39:37 CEST 2012
Geoff - wouldn't you also need an addresser or printer card to access over 64K? If I remember correctly the 4464's support 256 cycle refresh same as the 4164 except that they are 4 bits wide - two would make 64k. I would therefore assume the PAL was used as the MUX chip. If the wiring differs from the MI card, then the MI PAL won't work. However, if you find yourself with some time, you could trace out the schematic with an ohmeter - I've done this with several old cards. What I do is draw a rough copy of the board and components. Then using multi-colored inks (to help me keep the wires separate) and and ohmeter, I recreate the board connections which then gives me the schematic. If you can generate a schematic, I am relatively certain I could write the proper GAL equations for you. - John
> From: oltmansg at gmail.com
> Date: Tue, 31 Jul 2012 22:13:16 -0500
> To: coladam at adamcon.org
> Subject: [Coladam] Memory expander
> Hey guys, I have a memory expander with no silkscreen that is populated with 4464 DIP RAM and can (potentially) be expanded to 256k. I have no idea who made the thing, but I'd like to upgrade it. I have a feeling that it is a clone of the Micro Innovations card. This card has four jumpers on it, which I presume is used to select whether you're using it as a 64k card or a 256k one. On top of the missing 6 RAM chips, it is also missing a 7th chip, which I believe is a PAL/GAL (16V8?). Does anyone have any PAL equations or a dump of the PAL from the MI card? I'd like to max the sucker out.
> Also, anyone have a copy of a RAM tester program handy? I used to have one that would test up to 256k from the MI card, but I have no idea where this is now.
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