Non Conformance Report Nr. 002
24th November 2003
Step number 215-00 - X axis Low Level Signature post random test 0dB.
Run stopped at 102.5 Hz due to the presence of two peaks
below 100 Hz (68 Hz, 87Hz) in the response of channel 1 (reference
accelerometer for X axis test) as shown in attachment (figure
Furthermore a reduction of the frequency of the first mode was observed
during the full level random vibration random as shown in figure “random0db_acc1.jpg” in attachment.
Post-Test Inspection performed:
- Torque checked on the 32 M10 screws on the fixture: no change found;
- Tapping on the sidewalls: no apparent hollow sounds;
- Lift device attached to the tower and then to the crane;
- 32 M10 unscrewed starting from -Y sidewall in clockwise direction;
- Tower lifted above the slip table;
- Visual inspection of the bottom tray and flexures from below without
de-mating the flex cables form the test configuration showed no signs of
breakage or disturbance of the torque stripes of the screws;
- Check of the adapter plate with kapton tape: no presence of powder or
- Tower placed back on the adapter again waiting for further disposition
- Inform SLAC Project Office of the observed anomaly – completed;
- Inform INFN-Pisa to generate an inspection plan – completed.