BIAS CIRCUIT MRB              

Date:           3/11/2004

To:                Darren Marsh

Cc:                 Dr. Robert Johnson, Riccardo Bagagli, Dave RiCh

From:          Richard Gobin

RE:                MRB BIAS CIRCUIT LAT-DS-000192

Minutes of MRB meeting held in Bldg. 84 SLUO  8:00a.m. – 9:00a.m. March 11, 2004.

PN: LAT-DS-000192 rev. 6


Supplier: Parlex Corp., San Jose, Ca.

The following agenda was followed during this morning’s MRB.


1.      Present documented evidence/facts of failure or non-conformance.

a.      What, where, why, when, how?

2.      Overstress analysis or additional testing required?

3.      Suspected root cause? (present evidence as to why).

4.      Impact to inventory, WIP, supplier PO, already built product.

5.      Corrective action to prevent recurrence.

a.      Design, test, procedure options, trades & recommendation.

b.      Recommended Was/Is change description.

c.      Impacts to other subsystems.

d.      Affected documentation. (dwg, ICD, existing analysis, supplier EIDP).

e.      Verification plan to validate effective corrective action.

f.       Estimated costs & impact to schedule.

6.      Effectiveness of corrective action

a.      Any modification to performance capability.

b.      Impact on FMEA, reliability, risk assessment.

7.      Recommended final disposition(s):

a.      Rework

b.      Repair

c.      Return To Vendor

d.      Reclassify

e.      Scrap/Purge

f.       Use As Is


8.      Action items: who-what-ECD.




This primary focus of this MRB was to discuss the deviation of the released Bias Circuit drawing as stated in NCR 00065 as well as the impact to the science and technical justification regarding the first 50 Bias Circuit shipment from Parlex which are to be delivered with the 0.50 oz. copper foil. (0.50 oz per square foot.) Drawing note 4, states copper thickness to be 0.25 oz copper per square foot.


Cause of this discrepancy falls with the supplier not having the 0.25 oz copper available for flight production and LAT engineering accepting this drawing specification deviation. The 0.50 oz copper was available for immediate use in production from supplier, Parlex, with the understanding of the long lead time for the 0.25 oz copper. However, Parlex has notified LAT that the 0.25 oz copper will become available Friday March 12, 2004 for the next flight production run.


Due to the long lead time of the 0.25 oz copper, supplier, Parlex, was given a verbal approval to begin flight production for the first 50 Bias Circuits only. The critical path/schedule for these Bias Circuits would be adversely impacted for assembly into Towers at INFN if the production of the Bias Circuits was delayed. We currently do not have any flight approved Bias Circuits in inventory. We currently have a PO pending for future flight production.


Parlex is to have 50 flight Bias Circuits available for on site Source Inspection, Friday, March 12, 2004. Richard Gobin is to perform the source inspection, if flight Bias Circuits are acceptable, Richard is to hand carry all 50 flight Bias Circuits back to LAT QA Bldg. 33 to incoming receiving, who will follow procedure to receive flight hardware.


The agreed upon plan was to have the flight Bias Circuits packaged properly for delivery in Italy on Friday afternoon. Dr. Johnson was to receive 48 flight Bias Circuits on his way to the airport and hand carry to Italy.


Two flight Bias Circuits were to be diverted to Bldg. 25, Ton Nakashima, for first article dimensional inspection and documentation.


As of 2:00 pm today, I was notified by Jerry Clinton, that Parlex has had a problem with production and the 50 flight Bias Circuits will not be ready for Source Inspection on Friday as planned. It is anticipated, Source Inspection will be performed on Monday, March 15th.  This obviously impacts our agreed upon plan for Dr. Johnson to carry these 50 flight Bias Circuits to Italy on Monday, March 15th.


We are forced to adjust our plans and will document what will be agreed upon early next week.


The MRB has agreed to USE AS IS as a final disposition to NCR 00065. However, during the MRB discussion it was revealed the software for the Towers is impacted using the 0.50 oz copper foil. It is not promised that Italy can assure only a single Tower will utilize these flight Bias Circuits, there may be a co-mingling of the 0.25 oz copper and the 0.50 oz copper in more than one Tower.


LAT SAS, software engineer, Richard Dubois, will be notified to review this issue and his documented findings annotated in NCR 00065 prior to closure.


A secondary concern, which the MRB discussed, was how INFN is to assure proper documented traceability of these 48 flight Bias Circuits throughout their assembly and testing processes. The Bias Circuit drawing, note 11, requires all flight Bias Circuits to be marked with identifying serial numbers. The serial numbers for the first 48 Bias Circuits are to be annotated, along with the NCR number, 00065, on all travelers, utilizing these 48 Bias Circuits, at INFN for process and traceability assurance.


During the MRB discussion it was also revealed that early April, 2004, is when these Bias Circuits will be needed at INFN, due to production and testing schedule conflicts.  Because of this information, in addition to the information regarding the supplier, Parlex, slipping their production commitment, these flight Bias Circuits will be shipped via the ‘normal’ shipping means from Bldg 33, SLAC to Italy as soon as the Bias Circuits are received into SLAC Bldg. 33.







Action Items:


  1. Richard Gobin: Update NCR 00065 to reflect MRB issues and decision to Use As Is.
  2. Richard Dubois: Document findings regarding software impact using the 0.50 oz copper foil. Recommend what software modification is required.
  3. Richard Gobin: Perform on site Source Inspection @ Parlex. Report findings.
  4. Dr. Robert Johnson: Document science & technical impact/justification for using 0.50 oz copper.
  5. Richard Gobin: Create NCR for ‘sidebar’ trace issue regarding dwg. change per Jerry Clinton.
  6. Jerry Clinton: Document sidebar issue to assist with creation of new NCR.
  7. INFN: Annotate all serial numbered Bias Circuits onto traveler(s).
  8. INFN: Annotate NCR 00065 onto all traveler(s) utilizing the first 48 Bias Circuits.
  9. Jeff Tice: Package and ship all 48 flight Bias Circuits via normal shipping procedures to Italy next week.
  10. Dave Rich: Notify Tom Nakashima, two Bias Circuits will not be available for first article measurements Friday, March 12. Re-schedule with Tom Nakashima next week following source inspection.





     Richard Gobin