AirKon Posted June 22, 2019 Share Posted June 22, 2019 Hello, Sorry I use google translate. I'm trying to make the modification for the 64k. But nothing wants to work. I tried all 3 methods and checked my wiring 10 times. nothing, black screen. I put the 16k back in by removing the modifications and it works ( in 16k). I'm confused. Memory module TMS4464 from AliExpress, maybe the problem is this (bad memory)? Do you have any ideas? Thank you. Quote Link to comment Share on other sites More sharing options...
JR> Posted June 22, 2019 Share Posted June 22, 2019 You should be able to plug the 4464's into the motherboard with none of the other parts of the mod, and still have a working 16k machine. If not, the chips are probably bad. 2 Quote Link to comment Share on other sites More sharing options...
Rybags Posted June 22, 2019 Share Posted June 22, 2019 That's what I did - but of course you're only able to access the first 16k per chip so bad bits elsewhere wouldn't show. But that said, the Atari should still work if a 64K expansion had bad memory above 16K. Supposedly there was a bad upgrade description floating around, here's the text document that I used as a guide: 64k_upgrade_600xl.txt In theory if the upgrade wasn't quite done properly you could get mirrored Ram copies which would confuse the OS and probably give a black screen and no proper boot sequence. Quote Link to comment Share on other sites More sharing options...
AirKon Posted June 22, 2019 Share Posted June 22, 2019 Resolved Of the 10 chips purchased at Aliexpress, 7 are dead, 3 OK. I tested the chips with an arduino thanks to this assembly. => github ! With two good chips, it worked the first time. Thank you to everyone. 1 Quote Link to comment Share on other sites More sharing options...
Rybags Posted June 22, 2019 Share Posted June 22, 2019 That's a pretty abysmal failure rate - were these NOS type chips or do they look like they were pulled from something? I've got myself a stock of probably near 20 here - thanks to a bunch of late 80s to early 90s PC graphics cards that were otherwise useless. Quote Link to comment Share on other sites More sharing options...
AirKon Posted June 22, 2019 Share Posted June 22, 2019 8 minutes ago, Rybags said: That's a pretty abysmal failure rate - were these NOS type chips or do they look like they were pulled from something? I've got myself a stock of probably near 20 here - thanks to a bunch of late 80s to early 90s PC graphics cards that were otherwise useless. huuuummm It's probably that, they don't look new. I haven't thought about the old video card, I'm going to go through my archives. Thank you very much. Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted June 22, 2019 Share Posted June 22, 2019 (edited) just remember China was in the garbage recycling business for any country they could get so they could reverse snag all the tech from the garbage. After a fashion they started selling the parts back to us, sometimes they re labeled the chips based on what they thought they were or read as using a chips identifier... it is NOT uncommon to have fake or failed replicas, relabeled parts or even original parts pulled from a 15 year old device and sold as NEW. Sometimes that can be awesome for a part long since out of stock and no longer manufactured... I got burned with cleaned up 'new' Dallas Chips... all dead batteries made 30 years ago that were pulls sold as 'new'.. pffft... Edited June 22, 2019 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted April 14, 2021 Share Posted April 14, 2021 (edited) I could use a sanity check on this one, please. Somewhere, I can remember seeing a 64K upgrade for the 600XL in which pin 8 of U16 was jumpered to a via at about the 4 o'clock position relative to the cartridge slot. This did not require lifting R36, IIRC, and the other two jumpers from U5 and U6 remained unchanged. This mod did not go as far as soldering to the PBI port's contacts; it just used a via further down the board to achieve the same end result. If you happen to know which mod I am referring to, could you please point me in its direction? I could have sworn that I bookmarked it some time ago, but evidently that's not the case and searching for it is going nowhere. Edited April 14, 2021 by x=usr(1536) Quote Link to comment Share on other sites More sharing options...
+kheller2 Posted April 15, 2021 Share Posted April 15, 2021 From my upgrade. Swap the RAM, lift the two legs and wire as shown, pull the one chip and jumper. The jumper is between pins 8 and 10. (no it is not connected to 9, although the picture looks like it is, I should get a better shot). 2 Quote Link to comment Share on other sites More sharing options...
Sinjinhawke Posted April 15, 2021 Share Posted April 15, 2021 That picture makes it look so easy. My 600xl already has a (back in the 80's) 64K upgrade board installed otherwise I might try this. Quote Link to comment Share on other sites More sharing options...
Irata 008 Posted May 11, 2021 Share Posted May 11, 2021 Hi all, I am about to embark on upgrading my 2 600 Xls using the 3 wire method described in this forum with a view to then installing a Lotharek U1MB into one of them. Before I proceed, can anyone tell me if there are any compatibility issues with this upgrade? Is an 600XL upgraded using this method 100% identical to the Atari 800XL in operation? Also, can anyone tell me if U1MB causes compatibility issues with any significant software titles, or is it only incompatible with a few obscure titles or titles deliberately designed not to work with U1MB? Thanks for all the detailed guides and information on this forum! Quote Link to comment Share on other sites More sharing options...
Mazzspeed Posted May 11, 2021 Share Posted May 11, 2021 (edited) 26 minutes ago, Irata 008 said: Hi all, I am about to embark on upgrading my 2 600 Xls using the 3 wire method described in this forum with a view to then installing a Lotharek U1MB into one of them. Before I proceed, can anyone tell me if there are any compatibility issues with this upgrade? Is an 600XL upgraded using this method 100% identical to the Atari 800XL in operation? Also, can anyone tell me if U1MB causes compatibility issues with any significant software titles, or is it only incompatible with a few obscure titles or titles deliberately designed not to work with U1MB? Thanks for all the detailed guides and information on this forum! I have yet to find a title that won't run on my 600XL with 64k upgrade and U1MB - With the exception, of course, of certain titles deliberately coded in a way that they don't work with U1MB. Essentially the machine is identical to an 800XL with the exception of the lack of a monitor port on NTSC machines. Edited May 11, 2021 by Mazzspeed 1 Quote Link to comment Share on other sites More sharing options...
+x=usr(1536) Posted May 11, 2021 Share Posted May 11, 2021 1 hour ago, Irata 008 said: I am about to embark on upgrading my 2 600 Xls using the 3 wire method described in this forum with a view to then installing a Lotharek U1MB into one of them. Before I proceed, can anyone tell me if there are any compatibility issues with this upgrade? Is an 600XL upgraded using this method 100% identical to the Atari 800XL in operation? Also, can anyone tell me if U1MB causes compatibility issues with any significant software titles, or is it only incompatible with a few obscure titles or titles deliberately designed not to work with U1MB? Thanks for all the detailed guides and information on this forum! Since there are a couple of variations on how to accomplish the 3-wire upgrade, allow me to suggest using this one. The advantage to that particular method is that all changes are made to cheap, generic, readily-available ICs that cost less than $1 apiece to replace. Barring a freak accident, this pretty much eliminates the possibility of damage to the motherboard or proprietary components that are difficult to obtain. This is the upgrade I'm running on one of my 600XLs, and I have yet to find any compatibility issues. Quote Link to comment Share on other sites More sharing options...
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