The spacebar on my MacBookPro9,1 (15” Mid-2012 Non-Retina) replacement keyboard from iFixIt (item IF161-121-1) has failed....

Answering my own question: 1: I had to make up an extender from a standard 30 pin FFC (i chose Molex 0151660325 from Digi-Key) and a 40 pin extender adapter from Adafruit, #4523. If i had it to do over again i’d get a longer FFC, so it could twist and allow setting up the MBP in a normal orientation. 2: The key caps on the iFixIt IF161-121-1 pull straight off and snap on as for the original Apple keyboard. The space bar failed because the plastic tangs on the space bar key cap that hold one of its two long stiffening wires lost their ability to hold the wire in place. I wrote up a whole WWW article on my personal site, discussing all of this in-depth, in case anyone wants more information.

Just going through this with my 15” MacBookPro9,1. D key has been very intermittently flaky for awhile. Hold it and sometimes it will start working with no change of pressure and no even slight movement whatsoever. Sometimes nearby letters would do the same thing. Really seemed like a software issue. Would come and go, and be perfect for weeks. Today it was bad. Did the following: (1) Blew out debris with compressed air. There was a lot of it. Did not help. (2) Safe Boot to clear cache: did not help (3) Removed and reinserted the internal keyboard cable connector at the logic board: did not help (4) Tried a different OS user account: did not help (5) Tried a clean OS (same version: 10.12 Sierra) run off an external backup drive: did not help (6) Tried a different clean OS (High Sierra): not only did that not help, suddenly all of A, S, D, F, G were problematic (coincidence or related to earlier work), with D remaining the worst Did not do a PRAM zap today, but did one several weeks ago to cure this issue,...