ECR Title: Reposition the Vibration Absorbers Attached to the Output Faraday Isolator (OFI) Assembly	DCC No: E1300471-v1
Date: 21 May 2013
Requester: Matt Heintze	Impacted Subsystem(s): AOS/SLC
Description of Proposed Change(s): Move the vibration absorbers attached to the Output Faraday Isolator (OFI) Assembly so that they are not close to the septum plate. The two vibration dampers should be mounted on orthogonal faces and should be placed as far apart as practical (opposite corners, or at least opposite ends).
Reason for Change(s): There is limited access for attachment/detachment of the vibration absorber sub-assemblies when placed on the face of the OFI Assy which is adjacent to the septum plate.
Estimated Cost: no cost
Schedule Impact Estimate: no schedule impact
Nature of Change (check all that apply): Safety Correct Hardware Correct Documentation	Improve Hardware Improve/Clarify Documentation Change Interface Change Requirement
Importance: Desirable for ease of use, maintenance, safety Desirable for improved performance, reliability Essential for performance, reliability Essential for function Essential for safety	Urgency: No urgency Desirable by date/event: ____________ Essential by date/event: ____________ Immediately (ASAP) LLO is installing now and LHO will do so very soon.
Impacted Hardware (select all that apply): Repair/Modify. List part & SNs: ______________________ Scrap & Replace. List part & SNs:_____________________ Installed units? List IFO, part & SNs: _________________ Future units to be built/assembled	Impacted Documentation (list all dwgs, design reports, test reports, specifications, etc.): Revise sheet 2 of D0900456-v12 (LHAM5 Assy) Revise sheet 2 of D0901129-v5 (WHAM5 Assy) Revise D0900527-v2 (OFI Assy for L1) Revise D0901134-v2 (OFI Assy for H1)
Disposition of the proposed change(s): The disposition of this proposed engineering change request is to be completed by Systems Engineering and indicated in the “Notes and Changes” metadata field in the DCC entry for this ECR. The typical dispositions are as follows: Additional Information Required: in which case the additional information requested is defined. The ECR requester then re-submits the ECR with the new information using the same DCC number for the ECR but with the next version number. Rejected: in which case the reason(s) for the rejection are to be given Approved Approved with Caveat(s): in which case the caveat(s) are listed TRB: the ECR is referred to an ad-hoc Technical Review Board for further evaluation and recommendation. It is the System Engineer’s (or designee’s) responsibility to organize the TRB. The System Engineer (or designee) then makes a technical decision based on the TRB’s recommendation. Links to the TRB’s documentation (charge, memos, final report, etc.) are to be added to the “Related Documents” field for this ECR. CCB: a change request for approval of additional funds or schedule impact is to be submitted to the Configuration Control Board. Links to the CCB’s documentation (CR, etc.) are to be added to the “Related Documents” field for this ECR. Concurrence by Project Management: Acknowledgement/acceptance/approval of the disposition is to be indicated by the electronic “signature” feature in the DCC entry for this ECR, by one the following personnel: Systems Scientist Systems Engineer Deputy Systems Engineer