Date   : Mon, 08 Jun 1992 21:23:32 +1200
From   : Dave Sainty <terros@...>
Subject: ram

> up only one socket, take pin 1 (A14) to a random pin on IC76. (Little one, SW
> corner.) I particularly recommend pins 11 or 12 since then it stands a chance
> of working! (If it doesn't, then it ain't my fault - honest!) If he has a ROM
> board, then it will need 2 slots. Put the RAM in one, & take A14 to the notCS
> pin of the other. Obviously the pins which are wired to somewhere else need
> to be non-inserted into the socket.

This second method will not work, as the chip is not being selected for the
second bank. But, all is not lost.

If you want to use this method, run a ~10k resistor from +5v to the chips
notCS. you will need to put a diode between socket 1 notCS and the chip, and
also A14 and chip notCS. The line from A14 goes to socket 2.

as usual I can't remember which is anode and which is cathode... but both are
wired as so...

chip       |` |        one to A14, one to the socket notCS.
notCS------| >|-------     the socket one is tricky, I suggest you use a DIL
           |/ |            socket, to protect both the chip and the on board
                           socket...

This was my "mark II" sideways ram, before I found out where the rom latch
was. "Mark I" was a beauty! two 8k chips soldered on top of each other, with a
74LS04 sellotaped upside down on top! Looked a real mess, but do it with 2 32k
chips, and you'd have a single 64k module, very nice!