fisher@wsgate.DEC (Burns Fisher, MRO3-1/E13, DTN 231-4108.) (10/08/85)
<>
Bob Halloran asked about upgrading Atari 400 RAM to 64K.
I have not done this by replacing chips; I did buy a rather inexpensive
upgrade to 32K from someone on the net a few years ago. I think he used
16K chips, but just added an extra bank of them and made the board very
dense.
In any case, though, I wonder if you have used the 400 very extensively? If
not, you will find that if you are even a slightly reasonable typist, the
keyboard will drive you *>BATTY<* within minutes if not seconds! This means
that you will need to buy a full stroke keyboard to make the 400 useful,
and these are getting harder to find.
I suspect that by the time you get a keyboard and buy the chips, you will
come pretty close to the now heavily discounted price of an 800XL, which has
already 64K and an OK (but not superior) keyboard.
I would keep the 400 for use in some future project as a burglar alarm
controller (look at all those neat 4-bit I/O ports!) and get an 800XL or
even a 130XE (a bit more costly, but with 128K, I think).
Burns
P.S. Oh, you say you just wanted to play with hardware? Well, that's a
different story. Sounds like fun!
UUCP: ... {decvax|allegra|ucbvax}!decwrl!rhea!dvinci!fisher
ARPA: fisher%dvinci.dec@decwrl.ARPAekijak@ARDC.ARPA (Edmund S. Kijak, POINT) (10/10/85)
To: Burns Fisher,<fisher@ucb-vax.berkeley.edu> Speaking of keyboards for the 400, I noticed Radio Shack is selling a keyboard for $4.95. It looks like it came from a 600XL or 800XL - I think it even says Atari on it. Does anyone know if this would be plug compatible with the 400, or interfacable with very little effort? It has all the keycaps in the proper location - cursor control, reverse video key, reset, select, etc. and would be a pretty good deal for only 5 bucks if it worked. But I looked on the back of it and there are some IC chips mounted there (the 400 keyboard is just a set of membrane switches, there are no chips on it), so it may not be compatible.
abrams@MITRE.ARPA (Marshall D. Abrams) (10/11/85)
I believe it is a 1200XL keyboard. It is not compatible as-is with your 400. Probably you could strip off the components and wire your own matrix. I didn't find that to be too difficult, but I started with a clean keyboard. - Marshall D. Abrams, phone: (703) 883-6938 The MITRE Corporation, 1820 Dolley Madison Blvd. Mail Stop W458, Mc Lean, VA 22102
stekas@hou2g.UUCP (J.STEKAS) (10/14/85)
> I believe it is a 1200XL keyboard. It is not compatible as-is with your > 400. Probably you could strip off the components and wire your own > matrix. I didn't find that to be too difficult, but I started with a > clean keyboard. - Marshall D. Abrams In fact, the matrix on the 1200XL keyboard is the same as for the 400. Adapting it for the 400 requires removing the 2 ICs on the board and soldering jumpers from the (now) empty holes to the keyboard socket in the 400. One can figure out how to do this by reverse engineering the membrane keyboard or via the Tech. Ref. Manual. -Jim
Denber.wbst@XEROX.ARPA (10/18/85)
"In fact, the matrix on the 1200XL keyboard is the same as for the 400. Adapting it for the 400 requires removing the 2 ICs on the board and soldering jumpers from the (now) empty holes to the keyboard socket in the 400. One can figure out how to do this by reverse engineering the membrane keyboard or via the Tech. Ref. Manual." I went out and bought one of these keyboards (they look quite nice, and only $4.95!), but I don't have a TR Manual. Does anyone have the information I need to make the connections? Thanks. - Michel