tf_hh - sent you a PM. Posting here as well to see if anyone else has any thoughts...
Finally getting around to installing the 512 KB in my 600XL. Ran into a snag that I couldn't find any info on. This motherboard is fully socketed (AWESOME!!!), which poses a problem. The back of the boards pins will not sit flush in the ANTIC socket. The board is sitting against the upper chip. If I push it in, the board is slanted upward in rear.
After further testing, even if I get a low profile riser socket - even with the shield removed, the keyboard/top case will not sit flush with the unit. About a 1/4-1/2" gap.
So, it appears this expansion is not compatible with a "socketed" 600XL.
I´m very sorry - I forget to mention this fact in the installation manual and my hardware "catalogue" as well
Of course I will offer a full refund, if you want. Just PM me.
There´s no really good way to install it except direct soldering without the use of sockets. I don´t recommend that. Although I test every unit before shipping, and you also have test your computer, something may went wrong. And with a fixed, not replaceable PCB like this any kind of service is hard - maybe impossible. Desoldering a machine-head contact strip is pain in the *** - the chance of destroying any trace is much higher.
I updated the manual and catalogue files parallel with this post. If anybody has bought this PCB for usage in a 600XL, please contact me.