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Message ID: 5033     Entry time: Mon Jul 25 18:51:38 2011
Author: Manuel 
Type: Update 
Category: PEM 
Subject: STS-2 seismometer hardware testing with Jan 

[Jan, Manuel, Jenne]

Jenne called Jan to check and figure out why the Streckeisen seismometer (SN #100151) doesn't work, hence we checked the output of the seismometer boxes as we did last friday. (This is the problem of seeing the X and Y channels saturated, when we look at them on a floating 'scope, as in the linked elog entry.)

Jan unplugged and plugged again the orange cable into the seismometer and nothing happened.   Well, what Jan was listening for was "clicks" inside the seismometer indicating that it was receiving power.  We heard these, and moved on to examining the breakout boxes.  Also, we checked that we could hear the "clicks" (one per mass) when we pushed the mass-centering button on the little green companion box.

We weren't sure that the purple box was working properly, so since we had seen the blue box work last time, we changed the purple box with the blue box in rack 1X6.

The Z-channel of the purple box returns a correct signal, that means that all the masses in the seismometer work (because the Z-signal is a linear combination of the three masses U, V, W), the X and Y channel have a DC component of about 10 Volts, Jan said that the recentering of the seismometer masses could need all the night, so we keep the power of the box on. If tomorrow morning the X and Y signal won't  both be zero mean, we will open and check the box.

The power of the box is still on so that the masses can recenter overnight.

Edits by JD

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