Spancho

Count me in for a boxed version.

Count me in for at least one board.

https://www.collinsdictionary.com/dictionary/english/hundreds According to the Collins dictionary you are not quite right. 1. a large but unspecified number, amount, or quantity

Will there be a cartridge version?

Are the schematics of the Bit3 card already available somewhere? is the ROM protected? I am asking as you said it needs to be reverse-engineered.

I can test with another 48K board. I have to look through my stuff if I have 16K board without case. Do I have to disconnect any wire if I want to try the 48K board?

Hm, so only a quarter or third of the card is accessible. I wonder if that is due to a bad IC or or a bad soldering. Should I test a known good card with the current wiring?

So I finally found time to test the 400. The good news is that it is running, except the keyboard the first row doesn’t work. I replaced it with another one I have. But regarding the memory card ?FRE(0) states only 13326, so I guess it sees only 24Kib. I am not sure if I can test with a known good 48Kib card, due to the different wiring soldered to the main board. I don’t want to damage the card. On the memory card I checked already with a DMM for shorts, especially on the vias which had been repaired before. Any ideas what I can test to narrow down the issue?

Yes in deed they look very much like socket pins. I had the same impression. I hadn’t had time yet to reassemble the 400. Will do that most likely tomorrow.

Hi thanks for spending your time in looking at it. I am still cleaning all the boards and attach some more pics which hopefully get you a better visibility. The LS244 is indeed only soldered to cut of legs, so there is nothing below. I will test it this weekend to see if the whole 400 boots at all.

Hi #ClausB thanks for the schematic. Does the cable bridges on the underside of the main board are compatible with the Atari 48kb card type? l know there are either 2 or 4 cables to soldered and here are 5. Any way thanks a lot for you help.

This memory card is supposed to upgrade the 400 to 64Kb. I just wanted to know if that is possible in conjunction with the solder bridges on the underside of the main board. Maybe it’s a Mosaic clone or uses a similar technique? can someone who knows all the details of ram upgrades have look and give his opinion? Once I have cleaned all boards a checked for broken connections I will test if it works at all. Maybe it works as well in a mobo modified “only” for a 48kb upgrade.

Very nice XL. I wish you a lot of fun and entertaining.

The topic is about memory expansions by Atari to achieve more than 128Kb. I believe that is not possible with CX853, 52, 51 on a stock machine and 1064 neither.

The only Atari developed memory expansion modules for the 8-bit line were for the 1090 XL expansion box for up to 192Kb which didn’t make it to the market. Look here for more details: