ECR Title: Implement an additional patch panel to accommodate the in-vacuum WFS	DCC No: E1300757-v1
Date: 10/8/2013
Requester: Rich Abbott	Impacted Subsystem(s): ISC
Description of Proposed Change(s): Add an additional ASC RF patch panel, D1100905, for each in-vacuum WFS head. In the current design there is one patch panel terminating both frequencies of a WFS head. This patch panel is located between the corresponding two 4-channel demodulators. The new patch panel will be located below the lower demodulator. Each WFS patch panel will now serve the demodulator located in the slot above. The top row of the patch panel is dedicated for in-air WFS, whereas the bottom for the in-vacuum ones. Since there is only one test input per WFS head, it would be located in the upper patch panel. We also need to re-label the in-air cables of the in-vacuum WFS, since they are split by segments rather than frequency.
Reason for Change(s): The in-air and in-vacuum WFS share the demodulators, and in the current design also the RF patch panel. The proposed change would add separate patch panels to accommodate the in-vacuum WFS. Having the in-vacuum cables floating around and being forced to re-terminate them at the rear of the patch panel, whenever we change between in-air and in-vacuum WFS, isn’t reliable nor practical.
Estimated Cost: $3k for new patch panels.
Schedule Impact Estimate: none. The change needs to be implemented as soon as feasible.
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: _end of year__ Essential by date/event: ____________ Immediately (ASAP)
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	Impacted Documentation (list all dwgs, design reports, test reports, specifications, etc.): D1001425, D1001426, D1200666, E1200408
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