From: rmilner@zia.aoc.nrao.edu (Ruth Milner)
Subject: Re: SPARCstation ELC monitor woes
Reply-To: rmilner@zia.aoc.nrao.edu (Ruth Milner)
Organization: National Radio Astronomy Observatory, Socorro NM
Date: Thu, 27 Aug 92 20:04:39 GMT

In article <862@silence.princeton.nj.us> jay@silence.princeton.nj.us (Jay Plett) writes:
>In article <1992Aug25.082926.19478@icf.hrb.com>, jpl@icf.hrb.com (Joseph P. Laskowski) writes:
>> We have about 12 SPARCstation ELC's and have had various monitor problems on 
>> about half of our ELC's. 
>
>We have had 8 ELCs for just under a year and have had similar
>experiences.  In most cases, the guys in our electronics shop
>have been able to fix the problems by adjusting pots. [...]  
>We have also had to return 2 dead CPU boards for repair during
>the year.

We have had numerous monitor problems with our IPCs and IPXs, all purchased
this year. Not as high as half of the ~50, but easily a quarter of them, have 
had monitor "failures" of one type or another. While they were on warranty
they just got swapped by Sun, but the few that have failed since that time we
took a bit more time with, and found, like you, that in all but one case some
minor adjustments could be made using some controls we found when we took the
casing off.

What I, and others here, are wondering is whether these failures might be
caused by power quality problems. To start with, we are on rural power which
is subject to fluctuations. All workstations are equipped with surge protec-
tors, but supplying them all with UPSs isn't really an option (we have about
70 of them now, which represents triple the number we used to have in this
building). Essentially all of them are on office power, and we know we have a
problem with harmonics caused by the switching power supplies. Building 
neutral is running quite high, which I gather is one symptom of harmonics.

Has anyone out there had actual experience with computers causing power
problems and subsequent increased failure rates? If so, what did you wind
up doing to solve it? UPSs? Replacement transformers? Once you applied the
fixes, did you see a noticeable improvement? We are looking at depot repair
for these systems and if power problems cause more failures it's going to
get expensive.

I would also like to redistribute some laser printers in various places around
the building, but am a little wary of doing so at this time, since power qual-
ity is still an unresolved issue (we are taking steps to find out how much of 
a problem we really have) and I know that laser printers tend to be a headache 
(they sit idle drawing next to nothing and then suddenly pull 12A or whatever 
when laser, heater, rollers, etc. etc. all turn on at once). Would it be enough 
just to put each on its own 15A circuit?

Tales of any experience people have gained in the past couple of years would
be very welcome. I'm the first to admit that power engineering is not my
greatest area of expertise :-), so please keep it simple if possible.

Thank you!
-- 
Ruth Milner                          NRAO/VLA                  Socorro NM
Computing Division Head      rmilner@zia.aoc.nrao.edu
Newsgroups: comp.sys.sun.hardware,comp.sys.sun.admin