PSN-L Email List Message
Subject: Re: Haunted system misbehaving again
From: Larry Conklin lconklin@............
Date: Tue, 19 Jun 2012 21:18:47 -0400
Hi Larry,
Not a silly question at all, but one I've considered in the past. Have
carefully checked and cleaned around the pendulum, etc to get rid of any
possible webs or critters, with no noticeable effect.
Regarding the enclosure, it isn't much bigger than it needs to be to
enclose the volume surrounding the sensor. And I have a couple of power
resistors on an aluminum plate at the top of the box to try to create a
temperature inversion, but I've never been able to convince myself that
it makes any real difference. Maybe I need to make it a little hotter.
At one time I tried to take up as much of the empty space with baffles
made of corrugated cardboard, but that didn't seem to help either and it
made the cover of the enclosure surprisingly heavy. I wound up
scrapping that cover and making a new one out of celotex panels. It
would probably be a good idea to fill the empty space in this enclosure
with something light and insulating, like styrofoam.
But none of those possibilities really fit the history of the problem
very well. I could write a small book on all the things I've considered
and tried, several of which have seemed to cure the problem, only to
have it come back months later.
I really don't have any real reason to suspect the electronics, other
than I don't have any other ideas. The basement is humid, so at one
time I took the board out and baked it under a hundred watt light bulb
for a couple of days, cleaned it and put it back. No effect.
Since I can see corresponding glitches in the output of both channels,
if there is a problem with the board it either has to be upstream of the
point where the two channels separate, or possibly in the power supply.
But, with the limited test equipment I have, I don't see anything amis
in the power. And at one time, I decided it was worth the trouble, and
replaced the first stage op amp. No dice.
So.... What other ideas have you got?
Larry
On 6/19/2012 6:52 PM, Larry Cochrane wrote:
> Silly question Larry. Are you sure the noise is not being caused by
> spiders, also known as spiderquakes, or some other insect getting
> inside the enclosure? I guess it could also be air currents inside the
> enclosure. Do you have a lot of free air space inside your sensor box?
>
> Regards,
> Larry Cochrane
> Redwood City, PSN
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