ECR Title: ECR: CM Board Modifications (green finesse)	DCC No: E1400320-v1
Date: 7/8/2014
Requester: Daniel Sigg	Impacted Subsystem(s): ISC
Description of Proposed Change(s): Solution 1 - Change the second boost filter in the ALS PDH boards. See LHO alogs 9357 and 11503. C119: from 100n to 1u R78: from 82 to 165 Solution 2 – Change the common compensation filter to increase the zero from 200Hz to 4kHz. Modify first boost to give more gain at DC, pole lowered from 100Hz to 10Hz. See LLO alog 13484. R68: from 3.6k to 1.2k (Comm Comp) R69: from 18k to 120k (Comm Comp) R70: from 4.53k to 1.2k (Comm Comp) C121: from 220n to 33n (Comm Comp) R72: from 1.5k to 15k (Boost 1)
Reason for Change(s): The issue of the green ETM coatings requires a filter change in the ALS PDH board in the end station to account for the reduced finesse.
Estimated Cost: small (parts and labor)
Schedule Impact Estimate: None.
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: _Feb 2013____ 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.): D040180-F
Disposition (to be completed by Systems Engineering): TRB CCB Approved Additional information required. Define: [Requester re-submits with new information with the same DCC E-number for the ECR but the next version number.] Concurrence by Project Management: (Acknowledged Electronically in DCC) Project Systems Engineer: Dennis Coyne Project Systems Scientist: Peter Fritschel