You'll need two RAMchips for this upgrade. They should be of the type '64k by 4 bit'. Different numbers have been used to denote that a chip is a 64k by 4 bit chip, here are a couple of examples:
- 4464 - 2464 (Atari used these in the XEGS) - 41464
Plus some wire, and the usual stuff you need for soldering.
I'm not gonna tell you how to open or close the 600XL, if you can't find that out for yourself without damaging it, ask somebody else to do the upgrade for you. But what you should know is that the XL's keyboard is attached to the top of the case. This surprised me, as I'm an XE-lover.
(Don't worry, I'm using a text by Guus Assmann - a hardware guy well know way back when the Netherlands still had it's own Atari user group - as the basis for this text.)
Now look for U5 and U6, U11 and U12 and U15 and U18. Found them?
U5 = 74LS158 U6 = 74LS158
Atari might have used 74LS258's instead of 74LS158's.
U15 = 74LS375 U18 = 74LS32 U11 = 4416 RAM U12 = 4416 RAM
(There is a small notch on the RAMchips. Now is the time to look for it. Remember where it is, you'll need this later.)
Let's go on:
Lift pin 3 of U5 and connect it to pin 15 of U15 with a piece of wire.
Lift pin 10 of U6 and connect it to pin 9 of U15 with a piece of wire.
Lift pin 9 of U18 and connect it to pin 7 of the same chip (ground) using a piece of wire.
Remove the old RAM chips from the motherboard. If these RAMchips are soldered in, this is a good time to replace them with sockets. Get the precision sockets. They might be more expensive, but they ARE better. Now push the new RAMchips into the sockets, making sure the notches on the new chips point in the same direction as they did on the old chips.
Reassemble the 600XL and boot it. If everything is fine, typing BYE will get you to the SELFTEST. Go to the memory test. 40 block of RAM should show up. If they don't, or if you can't even get to the selftest, quickly switch of power and retrace what you did.
Do this at your own risk! If you do something wrong, that will be YOUR fault. Not mine, nor Guus's.
|Mathy van Nisselroy