[ANSS-netops] potential ETNA2 issue

[Jon Rusho]

We've encountered it on two instruments so far.  We tried loosening the 
bolt at one station and the signal seems back to normal.  Waveform image 
attached.

--jon


On 4/25/19 11:51, Smith, James wrote:
> Hello ANSS group,
>
> I have experienced "buzzing" issues with the ETNA2, and found out CGS 
> encountered a similar problem. Just wondering if anyone else has had 
> this issue with the units. Here is a response given by KMI support to 
> CGS regarding the matter:
>
> " Listening to the video and the fact that putting a finger on the 
> unit suggests that at least one of the EpiSensor components is 
> oscillating. We had one report of this but were unable to duplicate 
> the problem with the unit as returned which functioned normally even 
> after over-torquing the hold-down nut. Do we know if this unit was 
> torques with a torque wrench or by hand? I'm not sure who at KMI said 
> it couldn't be the bolt pressure but certainly if sufficient torque is 
> exerted the case can be deformed which could result in the sensors 
> going into oscillation. Hence, the essential question is was this 
> over-torqued or are some units susceptible to this at our suggested 
> torque. "
> r/Jim
>
>
> Jim Smith
> USGS-ESC
> 345 Middlefield Rd. MS 977
> Menlo Park, CA 94025
> (650) 329-4770 (office)
> (650) 229-4673 (cell)
>
>


-- 
===================================
Jon Rusho
Seismic Network Engineer
University of Utah Seismograph Stations

jon at seis.utah.edu
801-585-5523

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