There are a couple of sites still selling these and I could swear
someone had done a new PCB design with modern parts someplace:
http://cgi.ebay.com/US-Doubler-Upgrade-Atari-1050-800-XL-XE-ICD_W0QQitemZ14…
Curt
Geoffrey Reed wrote:
This is the way we burn the roms (now to find some
MCM6810 or compatible
rams and upgrade the ram in my old 1050 non double density) and make a US
doubler compatible 1050. Copied the rom from my other USDblr 1050, and need
to make the piggyback ram. ?course my DD 1050 needs new ram, it?s damaged
too :(