[TUHS] PDP 11/34a Serial Communications Problem
Noel Chiappa
jnc at mercury.lcs.mit.edu
Mon Feb 6 08:01:06 AEST 2017
> From: Mark Hare <markhare at buffalo.edu>
> I believe I have found the problem.
Excellent!
> Looking at the DL11-W, I saw that there is an uncovered trace on the
> circuit board just below the pins of the BERG connector. It appears
> that the exposed conductor ends of the cable were making contact with
> this trace, which shorted the entire cable together.
Shorting any set of DL11-W pins together still shouldn't have caused that
symptom, AFAICS.
I'm too lazy to pull out a DL11-W, and prints thereof, to check, but I suspect
that what actually happened is that trace carries some 'interesting' signal,
and it got grounded 'or something' by the exposed ends of the flat cable.
> I'm just glad that there doesn't appear to be any lasting damage.
Indeed! I was worried about that...
Noel
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