LIGO Document E1600021-v1

DCN, ETM Low Voltage ESD Driver Whitening Board Retrofit

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E - Engineering documents
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As approved by ECR E1500417, this DCN serves as formal notice to implement the addition of a D1500389 Signal Whitening PCB to the ETM, LV ESD Driver Chassis D1500129. Instructions for inserting the board are available below in the Notes and Changes. The addition of this circuit board, and the associated increase in ADC sampling rate will permit reasonable SNR visibility into ETM LV ESD actuation.
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Notes and Changes:
A whitening board has been designed and built for the ETM LV ESD chassis retrofit. A kit has been prepared for each site consisting of the following:

D1500389 Whitening Circuit Board for ETM LV ESD
Replacement front panel for D1500129 Chassis (ETM LV ESD Driver Chassis)
All required ribbon cables and DC power cables
Drilling template to create two mounting holes for the new circuit board.

Each kit will be specific (by chassis serial number) to an ETM LV ESD chassis. Care is needed to ensure the right kit is applied to a particular chassis (needs to have matching serial numbers).

Here's a summary of the chassis that have already been sent to both observatories and the proposed whitening board to go in each chassis:

Low Voltage ETM ESD Driver Chassis
Chassis S-Number ETM ESD Whiting BD Location
S1500069 S1600030 LLO
S1500067 S1600029 LLO
S1500072 S1600034 LLO
S1500066 S1600032 LHO
S1500068 S1600028 LHO
S1500070 S1600031 LHO
S1500073 S1600035 LHO
S1500074 S1600036 LHO

The process of doing the retrofit should take about 45 minutes or less per chassis. Here's a summary:

Remove chassis lid and front panel.
Replace front panel with new front panel of the same serial number and put all the cables and screws back in place.
Flip chassis upside down and use the template to locate two holes (4-40 clearance) on the bottom of the chassis.
Drill the holes and countersink such that a 4-40 chassis screw can seat without sticking up too much.
For worst results, be sure to leave lots of metal chips inside the chassis from the drilling operation.
Mount the new whitening board inside the chassis and plug in the ribbon and power cables per the attached photo.
Put the lid back on and restore the chassis to service.

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