Hi,

I'm looking for a memory upgrade (at least 256kB) for my 800XLF. I ordered one from Steve at AtariMax, but unfortunately not compatible with the Freddie chip. I considered the Satantronic 1MB upgrade, but my knowledge of electricity is not enough to build that. I need an english (unfortunately i don't speak German at all ) step-by-step "solder this pin to that pin" kind of installation manual.

Any help is very appreciated.

Just one more hing:
I have the 32-in-1 OS (by AtariMax) installed, so the memory upgrade must be compatible.

Hello,

There's no good reason why the memory upgrade should not be compattible with the freddy chip.
Do you have a schematic diagram from the memory upgrade?
Most other upgrades are not very easy to install.
I can send you more information but if you have a problem with soldering, then it will be very hard.
The other way to do this is that you send me the info on the memory update first.
Then we'll see what can be done. If it's too hard for you to do the work, you may send the computer and stuff to me. And I'll install a memory update. (And this will not be very expensive)
How many memory chips are in your computer?
And is there an empty spot where an IC can be installed on the board? (In that case, an update to 128KB is very simple, but may require the CO25698, if I remember the number correctly)

Best Regards,
Guus Assmann
Netherlands.

Howdy Guus, folks

guus hat geschrieben:And I'll install a memory update.

In that case, have a look at mine. It only needs some "bad Phi2 proofing" added. Check out http://www.holyoak.com/atari/8bitcomp.html

guus hat geschrieben:(...but may require the CO25698, if I remember the number correctly)

The chip you are looking for ist the CO25953. But if "U35" is mentioned on your the printed circuit board of your 800XLF (or any other XL/XE) you can also choose a GAL and a 74LS95B (check out my "special stuff" page at www.mathyvannisselroy.nl/special%20stuff.htm#co25953 to find the code that goes into the GAL) instead.

CU Mathy

Thank you for your help. Answering you questions:
- I can send you the installation manual (if you allow). It is a PDF document. The upgrade should be soldered in the place of U27, which doesn't exists on my MB (you can find the difference in the schematics of the XL and XLF). I contacted Steve and he told me that the upgrade is not compatible. Maybe you can find the way to install.
- I have eight RAM chips
- 128K is not enough
- Soldering is not a problem. Finding what to solder is the problem. I succesfully desoldered the BIOS.

Thank you for your help.
Jozsi

guus hat geschrieben:Hello,

There's no good reason why the memory upgrade should not be compattible with the freddy chip.
Do you have a schematic diagram from the memory upgrade?
Most other upgrades are not very easy to install.
I can send you more information but if you have a problem with soldering, then it will be very hard.
The other way to do this is that you send me the info on the memory update first.
Then we'll see what can be done. If it's too hard for you to do the work, you may send the computer and stuff to me. And I'll install a memory update. (And this will not be very expensive)
How many memory chips are in your computer?
And is there an empty spot where an IC can be installed on the board? (In that case, an update to 128KB is very simple, but may require the CO25698, if I remember the number correctly)

Best Regards,
Guus Assmann
Netherlands.

Hello,

The fun of Internet is just being able to cantact and help people!

And yes, you may send me the manual. (That is if it's not too big)
Then I'll have a look and let you know the findings.

It is not difficult to install 128K in an XE.
Matthy has given the right partnumber for the extra MMU.
It's also not very difficult to install an extra 256K into the now 130XE compattible computer. (I've deigned this many years ago)
Then you'll have 384K. And there's also a Dos2.5 that supports this amount in a Ramdisk.

BR/
Guus

Hello Jozsi,

It took some time, but I've dug up an answer.
I had to compare the schematics from the 800XL and the 130XE.
The upgrade should be usable in Your computer also.
But there's no U27 in your computer. So I looked at the connections that this gives.
And I guess you'll need the following:
Pin 3 from the U27 Connector to MMU pin 12 = A12
Pin 6 to MMU pin 3 = A13
Pin13 to MMU pin 4 = A14
Pin 10 to MMU pin 5 = A15
And if there's a trace from pin 1, then connect this to pin 33 of the freddy chip. (Left bottom om PCB, there's a chrystal or oscillator next to it)
The only thing I'm not sure of is this last wire.
For the rest, just follow the installation instructions.
I will also send you a PDF-File with the memory upgrade that I've designed for the 600/800XL.

BR/
Guus

Thanks Guus,

Do you think the logic implemented in the expansion board is compatible with my computer also? Maybe it is not enough to trace the pins. What does the U27 do?
Im waiting for the pdf. I think I'll send my computer to you to do a memory upgrade if your offer still stands

Thanks,
Jozsi

guus hat geschrieben:Hello Jozsi,

It took some time, but I've dug up an answer.
I had to compare the schematics from the 800XL and the 130XE.
The upgrade should be usable in Your computer also.
But there's no U27 in your computer. So I looked at the connections that this gives.
And I guess you'll need the following:
Pin 3 from the U27 Connector to MMU pin 12 = A12
Pin 6 to MMU pin 3 = A13
Pin13 to MMU pin 4 = A14
Pin 10 to MMU pin 5 = A15
And if there's a trace from pin 1, then connect this to pin 33 of the freddy chip. (Left bottom om PCB, there's a chrystal or oscillator next to it)
The only thing I'm not sure of is this last wire.
For the rest, just follow the installation instructions.
I will also send you a PDF-File with the memory upgrade that I've designed for the 600/800XL.

BR/
Guus

Hello Jozsi,

Of course my offer still stands.

The U27 is a 74LS157 or 74LS158.
This is a multiplexer.
All it does is connect Adress lines to the Ram-Chip.
First 4 adresses for RAS (Row Address Select) and the 4 other ones for CAS (Colomn Address Select)
The logic in the memory upgrade at least needs A12 to A15.
But now I'm writing this, I think that the other lines may be used as well.
The Logic will most likely also replace the Multiplexer.
Or is there still a TTL Chip on the upgrade?

BR/
Guus

The upgrade is actually a GAL chip. (and memory chips of course)

guus hat geschrieben:Hello Jozsi,

Of course my offer still stands.

The U27 is a 74LS157 or 74LS158.
This is a multiplexer.
All it does is connect Adress lines to the Ram-Chip.
First 4 adresses for RAS (Row Address Select) and the 4 other ones for CAS (Colomn Address Select)
The logic in the memory upgrade at least needs A12 to A15.
But now I'm writing this, I think that the other lines may be used as well.
The Logic will most likely also replace the Multiplexer.
Or is there still a TTL Chip on the upgrade?

BR/
Guus