>>> It is also possible that a capacitor has deteriorated in the >>> timeout one-shot >> >> I was beginning to wonder if it was a capacitor > > FWIW, while restoring my 11/45 and its RK11-C, I found several failed 74LS123 > dual one-shots in various places. > > Haven’t looked at the RL02 drawings yet, but it seems it was a popular part > in DEC designs; if you have one there it might be a more likely fail than the > associated small-value timing caps which tend to be fairly robust ceramics? > > They are pretty easy to diagnose with a chipclip and a logic analyzer. > > —FritzM.
Hmm, thinking about this a bit more though... I have tried three controllers, two r/w modules and two servo controllers. I'm beginning to think the drive is fine and there is a problem with the RLV21 controller. I measured the frequency of its pulses and they seemed to be within spec.
