BigFOX

I'll take one.

Well, I had to replace the switch on it as it was busted under all that tape. I also cleaned up the wiring work a bit and attached the switch with double sided stinky pad to the ROM board so it looks better. I haven't been able to test the "Impossible" coping part of it, however, the 4K extra memory part works fine. My 800 is sitting pretty on 52K of contiguous usable memory. However, if the Basic cartridge (and I am assuming any other cartridge but cannot test it) it is loaded after the extra 4K and it becomes invisible, but from what I have been reading elsewhere it is still usable if you know how to access it. I found this information about how the memory is mapped in the 400/800 machines. http://www.atariarchives.org/creativeatari/The_Mosaic_64K_RAM_Card.php Thanks again for all the help.

Thanks for the docs and the software. I won't be able to try it until I get an SIO2SD or something, but the documentation should answer some questions, If I can get that extra 4 K part of it working, that will be worth it just by itself.

Sweet! Thank you.

I am repairing an 800XL that only displays in greyscale. The potentiometer / variable resister that controls color is completely missing. I was wondering if anybody knows what range it is supposed to be so I can replace it.

Well, Option, Select, and Option+Select don't seam to do anything in any switch position. So It may be that "Impossible!" thing. Sounds like it needs special software to do what it does. Oh well, at least I know what it might be. Thank you both for your responses.

I got my Atari 800 at a thrift store when I was in JR High. It works perfectly, but its ROM card has some kind of after market mod on it with a toggle switch. To this day I have not been able to figure out what it does. The daughter card has no text other then Comp Side and Circuit Side. Attached is a picture of the ROM card with the mod attached. If anybody knows what this thing does, I would be very happy if you could tell me.