Replying to my own question in case it's searched in the future... With the exception of the CRT drive board and the display processor board, all of the other boards are the same between a 1240 and 1241 (except for model specific firmware in EPROM on the A09 processor board). The Catalyst Research lithium iodide battery failed in my unit (catastrophically) and in the process, practically destroyed the A09 processor board with it (in addition to significant corroding of the aluminum chassis in places). For a short time I considered testing my chops at rebuilding the battery damaged areas, but given the extensive damage, I opted to pick up a 1240 donor unit locally instead. That also allowed me to outfit my spare 1241 with a full complement of D2 cards too :) I did design and fabricate a "battery mod" that mounts a 2032 coil cell holder in place of the factory battery on the A09 card. Anyone who might want one can have some made from OSH Park if they like, the project is shared here - https://oshpark.com/shared_projects/oAsZEWxr In case anyone is still using the 1240/1241, replace those batteries in the main chassis, as well as those in any RAM PAK's you may have. I do have some viable leftovers from the donor 1240 if anyone is in need of parts - front panel, CRT, A05 (keyboard), A08 (backplane), A10 (I/O processor), A11 (mono display processor), A14 (trigger) boards, and many of the chassis mechanical parts. Email me if there is something specific you need. FYI. --Brad ----- Original Message ----- From: "bradg" <bradg@digitalplains.net> To: "Technical Tools Mail List" <techtoolslist@flippers.com> Sent: Monday, August 5, 2019 11:29:30 AM Subject: [Techtoolslist] Tek 1240/1241 Mainframe Card Compatability? Hoping there might be a Tek guru out there that can answer this off the top of their head... Are the basic mainframe modules/boards compatible between the 1241 and 1240 (excluding the video card, obviously)? I can't find my paper service manuals right off to research, and PDF manuals are a pain to skim for me anyway. I have a bad "Control Processor" board in my 1241 (long story, yes, it's definitely toast, physically damaged) and am wondering if they are the same between the 1240 and 1241 (sans probably different firmware in the EPROM's). If they are the same, I'd just pick up a cheap locally available 1240 donor on eBay and go from there. Thanks for any insight anyone can give! --Brad _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/ _______________________________________________ Techtoolslist mailing list Techtoolslist@flippers.com https://pairlist7.pair.net/mailman/listinfo/techtoolslist FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment Archive site: http://seven.pairlist.net/pipermail/techtoolslist/