On Fri, 02 Feb 2018 12:35:22 +0000, AnthonyL wrote:

We had no end of intermittent problems with a repeater especially on one
or two segments.

Had to get specialists in, with fancy equipment and they were scratching
their heads. For some reason I happened to measure the shielded earth
to a socket earth - there were volts there!!

Yep the offices was two houses, joined together, the front being on one
transformer and phase and the back being on a different transformer and
phase with earth differences. Sparky redid the fuse boxes/earths etc
and no more problems. A long time ago but I don't think the two
supplies into one property was a permissable arrangement for similar
reasons to the problems we encountered.

Had that problem. We had a nicely refurbed computer room, with the 'old'
one at one end and the 'new' one at the other. Two separate power inlets,
the 'old' one being direct mains, and the 'new' one being via a motor
alternator.

All worked OK until we were testing a homebrew operating system on the
new machine; this used a PDP-11 as the front end. We kept getting
unexplained parity errors on the interface between the PDP-11 and the new
machine.

It took them a long time to switch the PDP-11 to the same power inlet
(and earth) as its companion. It had been there for a while, in another
incarnation, and was ol the 'old' power.




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