Curses... all memory out, problem persists. Noted that one of the 4116s
is missing a leg, and another has had a prosthetic leg added at some
point. Next step: turns out +5V is shorted to ground. Looks a lot like
one of the (presumably tantalum?) +5V HF noise capacitors has shorted.
Anyone know any tricks that could save me from having to unsolder and
test them one by one? There are a lot of the things, >30 at a glance.
Will persevere...
Cheers,
Mike