MCM-120 was one of the first three MCM's we received. It was tested at the time (early June 1999?), but did not officially go through the QA tests. This was probably the very first MCM we tested. It had capacitors on backwards, which caused them to burn up. For this an other reasons, the surface mount components have been replaced twice. However, after all of these problems, it was tested enough to know that it was working. Because of time pressures, this was considered sufficient testing and the MCM/output cable combination was attached to a Silicon detector/cable combination in June 1999.

Jehanne also noted that the surface mount components seemed to be loose when she looked sometime during the week of August 9-13, 1999. Because of the loose components, this MCM was tested sometime during the week of August 8-13, 1999. Again, it did not officially go through the QA procedure, but it was working.

On 18-Aug-99, this MCM was put through the official QA program. It failed completely. Because it worked prior to this test, the most obvious conclusion is that it was broken during handling. However, we do not know ehen or how this happened. Many connections on this MCM are now open, including most power connections. Our tests show that the connector from the Power-comm board and the associated cable are OK. We can not tests all of the wired bonds, but we were able to check that at least some of them are intact. The problem seems to be on the MCM itself -- power lines on the side of the MCM nearest the power/comm board are connected, but those on the far end (nearest the Si detector) are not connected to the input power lines. We think that this MCM is starting to become delaminated, but are not certain.

Conclusion: This MCM does not work. It once worked and the failure does not seem to be a problem in MCM production, but a problem in subsequent handling of the MCM/detector combination.