Hi Steve,

Boy, THAT is an interesting piece of news.  I've never had my system go 
dead (other than due to having it go too far out of level, which it 
seems to routinely do when I'm away from home on a vacation). But 
extreme LF noise is the defining symptom of what I'm fighting. I was 
looking at my notes and a data file I saved from an earlier episode of 
this problem.  The thing had been running with an RMS noise level of 20 
counts or so.  I adjusted the leveling screw and the noise immediately 
went to RMS of around 300 counts, and stayed that way for at least a 
month, despite everything I tried to find the cause.  Unfortunately, my 
notes don't record how that episode was finally resolved.

Sounds like we should get together and hire a Gostbusters squad!

Larry

On 6/21/2012 9:16 PM, hsvham wrote:
> Hi Larry (Conklin) -
> I'm just now catching up on the PSN email traffic and the "Haunted 
> System" thread.
> FWIW, my SG seems to do the same thing as yours from time to time.  I 
> built the sensor many years ago, and built up the electronics board 
> from Larry Cochrane's schematics.  I am still running it at present, 
> alongside my much newer force-balance vertical instrument.
> Every so often, the SG channel will either (1) go totally dead silent, 
> or (2) get extremely noisy.  In the past when I see this, I'll power 
> down the instrument and run through the various connectors in the 
> system, re-level the sensor, and fire it back up.  And everything is 
> OK in that channel for the next several weeks / months.  I have yet 
> to successfully trace the problem to an offending connector or 
> electronic part.
> So my SG seems "haunted" by the same ghost as yours. ...go figure...
> Steve Jones
> AlabamaQuake
>


  
    
  
  
    Hi Steve,

    

    Boy, THAT is an interesting piece of news.  I've never had my system
    go dead (other than due to having it go too far out of level, which
    it seems to routinely do when I'm away from home on a vacation). 
    But extreme LF noise is the defining symptom of what I'm fighting. 
    I was looking at my notes and a data file I saved from an earlier
    episode of this problem.  The thing had been running with an RMS
    noise level of 20 counts or so.  I adjusted the leveling screw and
    the noise immediately went to RMS of around 300 counts, and stayed
    that way for at least a month, despite everything I tried to find
    the cause.  Unfortunately, my notes don't record how that episode
    was finally resolved.  

    

    Sounds like we should get together and hire a Gostbusters squad!

    

    Larry

    

    
On 6/21/2012 9:16 PM, hsvham wrote:

    
    

      

        

          

            

              
Hi Larry (Conklin) -
              
I'm just now catching up on the PSN email traffic and
                the "Haunted System" thread.  
              
 
              
FWIW, my SG seems to do the same thing as yours from
                time to time.  I built the sensor many years ago, and
                built up the electronics board from Larry Cochrane's
                schematics.  I am still running it at present, alongside
                my much newer force-balance vertical instrument.  
              
 
              
Every so often, the SG channel will either (1) go
                totally dead silent, or (2) get extremely noisy.  In the
                past when I see this, I'll power down the instrument and
                run through the various connectors in the
                system, re-level the sensor, and fire it back up.  And
                everything is OK in that channel for the next several
                weeks / months.  I have yet to successfully trace the
                problem to an offending connector or electronic part.  
              
 
              
So my SG seems "haunted" by the same ghost as yours. 
                ...go figure...
              
 
              
Steve Jones
              
AlabamaQuake