Tracker Status

January 7, 2005

Tower A:

- Tower A shipping was delayed a week to investigate and repair a short circuit on a signal line of cable C6. A termination resistor was shorting to the closeout edge, due to an error in the cable design that positioned the resistors wrongly. Kapton tape was used to isolate the resistors, and all 8 cables are now working.

- Other than the now-repaired short, the environmental tests were successful.

- The Tower-A preship review will take place Monday morning at 8:00 PST, December 10.

- All the hardware for receiving and testing the Tower at SLAC is in place, except for one table, which should arrive Tuesday.

Tower B:

- The trays are all stacked and some of the cables put on. Further assembly was delayed about 3 days following Tuesday’s cable MRB, in order to send cables from SLAC to replace those in Italy that had defective coupons.

- The replacement cables have arrived in Pisa and will be installed today.

- Tower-B environmental testing is scheduled to start January 17.

Tray Assembly:

- Assembly of trays for Towers 1, 2, and 3 will proceed starting next week at G&A using MCMs from the existing stock, assuming resolution of ASI funding issues.

MCMs:

- Rework of MCM pitch adapter delaminations completed at SLAC, and the MCMs were retested this week to prepare them for shipping to Pisa.

- Teledyne completed rework on 20 MCMs that were returned to them because of soldering and conformal coat issues. They all tested good and will be shipped to SLAC soon for thermal cycles and burn-in.

- Teledyne restarted MCM production before Christmas, but it never progressed beyond MIP-1. The pitch-adapter attachment failed with massive numbers of cracked traces, such as was never seen previously. A concerted effort is underway to understand the cause and take corrective action, with several parallel paths being pursued.

- Pitch adapter prototypes were received from Dyconex in Switzerland. They have far less problem with cracking than the Parlex pitch adapters, but the results were still not acceptable, so the problem appears to go beyond the pitch adapters. Issues with the PWB radius machining and the assembly tooling are being pursued.

- A PR was put out to purchase more GTFE wafers, to make up for yield losses in the MCM production.

Flex Circuit Cables:

- Introduction of a new water-blast cleaning process at Parlex appears to resolve the problems of barrel-trace separation, but a few tests are still pending.

- Other issues with cable assembly are also being resolved.

- SLAC is waiting to receive cables from the revised process.