I have an SG sensor that has intermittently had serious noise problems, 
literally for years.  Mechanically, it is very similar to the design 
that is shown on Larry's PSN web site, and it uses Larry's electronics 
board, which I believe he is no longer selling.

When the thing is running properly I've been quite happy with it. But 
occasionally, for reasons I have never been able to pin down, it 
exhibits extreme low frequency noise, to the point where it is basically 
useless.  The current episode began with the system running very well, 
but it was in need of leveling, which I've typically need to do every 
couple of weeks or so.  Before I adjusted the leveling screw, it was 
quiet.  After messing with it it became extremely noisy.  So, you'd 
believe that it was some sort of mechanical problem, right?  And I've 
had several other episodes that began the same way.  This time, when I 
brought it upstairs on the bench, I did in fact discover that the lock 
nut on the leveling screw was loose, and I "fixed" the problem by 
re-tightening it.  Ran pretty well for a week or so thereafter, but not 
really as quiet as it should be.  Then, it spontaneously got quite noisy 
again, interspersed with periods where it ran ok.

I have a lot of other history with seemingly mutually exclusive 
symptoms/probable causes, but the bottom line is I don't have a clue 
what is really going on.  I'm tempted to believe that there is something 
subtle wrong with the electronics board, but in past attempts to trouble 
shoot it, haven't been able to find anything.

If there is anyone out there who has one of Larry's SG boards that 
they're willing to part with, I'd be interested in buying it.  If for no 
other reason than to rule out the board as the source of the problem.

For the curious, I have a little web page that I dump drum reports up to 
daily. The report for today (so far) shows a particularly noisy day, but 
does include the quake that happened in the Aleutians this afternoon.  
The page also shows drum reports from the day this round of the problem 
started.  The day started just fine, until the big transient that 
resulted when I went down and adjusted the leveling, at which point all 
hell broke loose.  You can also see the consequences of two subsequent 
leveling adjustments later in the day.  After that data was recorded, I 
didn't mess with the thing for maybe a week, until I finally got around 
to taking a closer look at it, at which point I realized that the 
leveling screw was loose and re-tightened it.

I'd be very interested in anyone's thoughts on this problem.  The link 
to my web page follows:

http://home.roadrunner.com/~lwconklin/

Larry Conklin
Liverpool, NY

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