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Message ID: 575     Entry time: Thu Jun 26 18:24:28 2008
Author: Yoichi 
Type: Update 
Category: PSL 
Subject: FSS input ofset slider problem - fixed 
I checked the FSS servo interface board and found that a LT1125CSW used to differentialize offset channel was broken (no virtual short).
So I replaced it. Now the slider is working.
The op-amp was hitting the rail. So it seems like we had been applying the maximum offset to the FSS input all the time.
The reason why the FSS loop still worked with the large offset is that the applied offset (~14V) is attenuated by a factor of 500 at the summing point.
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