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Entry  Thu Dec 16 15:10:18 2010, josephb, kiwamu, Update, CDS, ETMY working at the expense of ETMX 
    Reply  Fri Dec 17 02:22:06 2010, kiwamu, Update, CDS, ETMY damping: not good 
       Reply  Mon Dec 20 10:06:36 2010, kiwamu, Update, CDS, ETMY damped 2010Dec18.png
Message ID: 4068     Entry time: Fri Dec 17 02:22:06 2010     In reply to: 4065     Reply to this: 4075
Author: kiwamu 
Type: Update 
Category: CDS 
Subject: ETMY damping: not good 

  I made some efforts in order to damp ETMY, however it still doesn't happily work.

 It looks like something wrong is going on around the whitening filters and the AA filter borad.

I will briefly check those analog parts tomorrow morning.

 

- - -(symptom)

Signs of the UL and the SD readouts are flipped, which I don't know why.

At the testpoints on the analog PD interface board, all the signs are the same. This is good.

But after the signals go through the whitening filters and AA filters, UL and SD become sign-flipped.

I tried compensating the sign-flips by changing the sign by means of the software, but it didn't help the damping. 

In fact the suspension got crazy when I activated the damping. So I have no idea if we are looking at exactly right readouts or some sort of different signals.

 

- - -(fixing DAC connector)

 I fixed a connector of the DAC ribbon cable since the solderless connector was loosely locked to its cable.

Before fixing this connector I couldn't apply voltages on some of the coils  but now it is working well.

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