Bouncing this back up because I was over in Kent today meeting the very skilled Miles Whitehead to pick up and drop off a lens (not the same lens, obviously), and I asked about this issue. According to him, there's nearly never a case of the electronics failing on an old camera, he says they've been pretty much sorted since the A1 came out. Virtually everything can be traced to a mechanical fault. He's got a T90 too and agrees they're practically bullet proof
Of course, this was before I
took mine for a swim so we'll have to wait until the morning to see how that works out. :bonk: