5 Jun
2009
5 Jun
'09
8:21 a.m.
On Thu, 4 Jun 2009 15:15:24 -0400
Ethan Dicks <ethan.dicks at gmail.com> wrote:
We had something like that happen with our Qbus
COMBOARDs when an
early customer installed theirs into a Qbus backplane that didn't
provide -15V (which is, ISTR, most of them). Things didn't make sense
until we figured out the lack of negative voltage to the 1488s/1489s.
Every Qboard after that had a DC-DC converter on it (and I still have
dozens of those, new on the slab of foam).
Even DEC did it. The, IIRC, DHV11 QBus 8
line RS232 has a DC-DC
converter on it. I saw several DHV11 where the poted torroidal
inductivity of this discrete DC-DC converter was ripped of the PCB.
--
tsch??,
Jochen
Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/