My question.. aside from manuals and the tech docs does anyone have any anecdotal info, advice or test procedures related to DEC core RAM and intermittent stuck bits? Shielding tips?
I haven't had to do much repair work on PDP-11 core, but on PDP-8 core I've found them to be somewhat sensitive to power supply voltage and cleanliness...Ripple creeping in has caused me the problems you're seeing on that PDP-11 core. The other thing I've had issues with is the temperature compensation circuit; an open thermistor has bitten me more than once.
-Dave
Thanks Dave. I only have failures of bits flipping on, I have never seen a bit erroneously flip to off. I have traded out all cards, no changes detected surprisingly. .. so your power supply ripple suggestion makes sense. B