Subject: UPGRADE: Newell 256K Memory to 130XE Compatable
NEWELL 256K MOD
Information supplied by:
Installed, Tested and Proofed by:
Sysop of The Stormbringer BBS
300/1200/2400 Baud Bangor, WA.
Until now, most of the 256K Memory upgrades have been virtually
incompatible. The three main memory upgrades had their pro's and con's, but
the thing most needed was a way to make them compatible with each other.
This modification will make a Newell 256K Atari 800XL compatible with,
the PD "130XE compatible" 800XL 256K project, as well as the RamboXL 256K kit
for the 800/1200 XL's. In other words, Make Your Newell 256K 800XL compatible
with Most of the other 800/1200 XL and 130XE Mods.
The problem is a simple one. It seems the difference is in how the
different modifications use Bit 5 off of the PIA chip. All you need to do is
provide a way to invert this one signal in the Newell upgrade and it will
operate like the Public Domain and RamboXL upgrades with all the excellent
error checking the Newell 256K Provides. If you also provide a way to switch
it back, it will act like the Newell again, Thus giving you the Best of Both
Neither this BBS or the author shall assume any liability or responsibility
for any damage real or personal for this design due to the inability to
control practices or construction techniques in building this circuit. BE
Now For The Modification...
First, install a single pole double throw (SPDT) switch on the back of
your computer or wherever you will feel the most comfortable with it. Now I
am assuming you have already installed the Newell 256K as per its
instructions. Disconnect the lead from PIA chip pin 15 that leads to pin PB5
of the Newell board and connect it to the CENTER pole of the switch you just
installed. Then solder TWO wires to Pin 15 of the PIA chip the same way the
wire you just removed from there was soldered on. Connect ONE of these wires
to one of the other two possible (outer) poles of the switch. When the
Switch is in this position, it will act like a Normal Newell 256K UpGrade.
Now solder the second wire coming from the PIA chip pin 15 to pin 5 of the
U19 chip on the Main Atari Mother Board. This is a spare gate. Then solder
a wire from pin 6 of U19 to the remaining pole of the switch. When in this
position, the Newell will act like the other Memory UpGrades.
After you have put your 800XL back together again, boot up your system
with Sparta DOS in the Newell Mode and use the RD.COM file. It should
identify your computer as a 130XE and give you a 64K Ramdisk. Now turn the
system off and boot the system as before only this time put the switch in the
what I call the Rambo Mode. It should identify your computer as a 256K 800XL
and give you a 192K Ramdisk. Next use the Ramdisk in both Modes to make sure
you have not damaged something (like rams, etc.) while you were inside the
computer. If all goes well, which it should, you now can run almost all of
the software designed for the various 256K XL mod's and most software for the
Atari 130XE..... I personally have not found anything that won't run on my
Newell Modified 800XL yet.
If you have any Questions and/or Comments, I can be contacted on:
The StormBringer BBS