joeventura Posted July 4, 2007 Share Posted July 4, 2007 (edited) So I grabbed an Atari 400 off Ebay because it had a BKEY keyboard, Just knew that since the owner put a BKEY on it then there had to be a memory upgrade in there, So I opened it up to find the hacked 16k Board (with Dynamic technologies added PCB) and the solder jumpers on the bottom of the motherboard, of course one wire has to be lose (one to the left of the cartridge slot) and I can't see where it was tacked on, any ideas? Edited July 4, 2007 by joeventura Quote Link to comment Share on other sites More sharing options...
walter_J64bit Posted July 4, 2007 Share Posted July 4, 2007 WOW, Good luck with that if you do get back in working order is going to have 48K? Quote Link to comment Share on other sites More sharing options...
Rybags Posted July 4, 2007 Share Posted July 4, 2007 (edited) That looks like 64K to me. Not sure how the bank select works with those on the 400/800 - the extra memory banks map to $C000-$CFFF. Maybe it uses CARTCTL in some way? In which case it might take an input from that line on the cartridge slot. Can you trace the unattached line to a point on one of the RAM chips? That would provide a lot of information. ed: I couldn't find any info on how the bank-select works with such upgrades. Another possibility is that it just uses location $CFFF or something. But, if your upgrade is 64K, then it would have to employ extra logic to achieve it's bank-switching. Edited July 4, 2007 by Rybags Quote Link to comment Share on other sites More sharing options...
walter_J64bit Posted July 4, 2007 Share Posted July 4, 2007 What can you do with a 64K 400? I know It can't run XL/XE programs, but the idea having a 64K 400 is cool! Quote Link to comment Share on other sites More sharing options...
joeventura Posted July 4, 2007 Author Share Posted July 4, 2007 Strangely, with the wire detached, it fires up and I get 37902 when I type ? Fre(0) Hmmmmmmmmm Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted July 4, 2007 Share Posted July 4, 2007 Looking at your picture of the mainboard, try attaching the wire to the bottom left pin on the cart slot. I was just going through a bunch of stuff from the 3 lots of Atari stuff I got and came across the documentation for a 48K mod for the 400, using a 16K board for the mod. Let me know if it works with the connection I listed. Quote Link to comment Share on other sites More sharing options...
Rybags Posted July 4, 2007 Share Posted July 4, 2007 You'll still get the same free RAM with BASIC. The extra RAM in non-contiguous when a cart is present since it's after the cart address area. Try POKE 50000,111 : ? PEEK(50000) POKE 50000,222:? PEEK(50000) to see if there's any extra RAM at that area. Quote Link to comment Share on other sites More sharing options...
mimo Posted July 4, 2007 Share Posted July 4, 2007 I was just going through a bunch of stuff from the 3 lots of Atari stuff I got and came across the documentation for a 48K mod for the 400, using a 16K board for the mod. Do you have the details for this? I would really like to upgrade my 400, but cant find a memory upgrade anywhere Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted July 4, 2007 Share Posted July 4, 2007 I was just going through a bunch of stuff from the 3 lots of Atari stuff I got and came across the documentation for a 48K mod for the 400, using a 16K board for the mod. Do you have the details for this? I would really like to upgrade my 400, but cant find a memory upgrade anywhere I will scan the docs and post them. Quote Link to comment Share on other sites More sharing options...
mimo Posted July 4, 2007 Share Posted July 4, 2007 Thanks very much Quote Link to comment Share on other sites More sharing options...
+warerat Posted July 4, 2007 Share Posted July 4, 2007 So I grabbed an Atari 400 off Ebay because it had a BKEY keyboard, Just knew that since the owner put a BKEY on it then there had to be a memory upgrade in there, So I opened it up to find the hacked 16k Board (with Dynamic technologies added PCB) and the solder jumpers on the bottom of the motherboard, of course one wire has to be lose (one to the left of the cartridge slot) and I can't see where it was tacked on, any ideas? I'm pretty sure this goes to the leftmost pin on the bottom row of the cart slot based on your second picture. RD4 and RD5 aren't connected in the 400 and you need them to disable the RAM when cartridges are inserted. Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted July 4, 2007 Share Posted July 4, 2007 (edited) Thanks very much Here it is. I am also going to post in a new thread. Atari_400_48K_Memory_Upgrade.pdf Edited July 4, 2007 by Guitarman Quote Link to comment Share on other sites More sharing options...
Defender II Posted July 5, 2007 Share Posted July 5, 2007 I was just going through a bunch of stuff from the 3 lots of Atari stuff I got and came across the documentation for a 48K mod for the 400, using a 16K board for the mod. Do you have the details for this? I would really like to upgrade my 400, but cant find a memory upgrade anywhere MyAtari has them for sale on their website and also eBay once in awhile. Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted July 5, 2007 Share Posted July 5, 2007 I was just going through a bunch of stuff from the 3 lots of Atari stuff I got and came across the documentation for a 48K mod for the 400, using a 16K board for the mod. Do you have the details for this? I would really like to upgrade my 400, but cant find a memory upgrade anywhere MyAtari has them for sale on their website and also eBay once in awhile. Yes, that is the way to go if you don't want to do the 16K card mod. That is the Atari released 48K memory upgrade kit for the 400. I have that one in mine. Quote Link to comment Share on other sites More sharing options...
mimo Posted July 5, 2007 Share Posted July 5, 2007 unfortunately the 48K 400 upgrade is no longer listed at B+C Quote Link to comment Share on other sites More sharing options...
+Guitarman Posted July 5, 2007 Share Posted July 5, 2007 (edited) unfortunately the 48K 400 upgrade is no longer listed at B+C I have an upgraded memory card in my Long Beach lot that I have no use for. I can look over it and make sure it is wired correctly and test it. Of course, you will have to do the motherboard mods yourself. Let me know if you're interested. Edited July 5, 2007 by Guitarman Quote Link to comment Share on other sites More sharing options...
mimo Posted July 5, 2007 Share Posted July 5, 2007 oooooh yes!!!! thanks Quote Link to comment Share on other sites More sharing options...
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