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Entry  Thu Jul 12 21:16:25 2018, aaron, Update, OMC, Checking OMC Electronics 
    Reply  Sat Jul 14 16:04:34 2018, aaron, Update, OMC, Checking OMC Electronics Screenshot_2018-07-14_17.53.40.pngScreenshot_2018-07-14_17.57.17.png
       Reply  Sat Jul 21 01:14:02 2018, gautam, Update, OMC, PZT Jena driver board check 
Message ID: 14072     Entry time: Sat Jul 14 16:04:34 2018     In reply to: 14060     Reply to this: 14095
Author: aaron 
Type: Update 
Category: OMC 
Subject: Checking OMC Electronics 

Next check is the DCPD/OMMT Satellite Box

I traced a cable from the OMC electrical feedthrough flanges to find the DCPD/OMMT Satellite Box (D060105). I couldn't find the DCC number or mention of the box anywhere except this old elog.

Gautam and I supplied the box with power and tested what we think is the bias for the PD, but don't read any bias... we tracked down the problem to a suspicious cable, labelled.

We confirmed that the board supplies the +5V bias that Rich told us we should supply to the PDs.

We tested the TFs for the board from the PD input pins to output pins with a 100kHz low pass (attached, sorry no phase plots). The TFs look flat as expected. The unfiltered outputs of the board appear bandpassed; we couldn't identify why this was from the circuit diagram but didn't worry too much about it, as we can plan to use the low passed outputs.

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