Due to limited maintenance time between diagnosis and action, we triaged the fan failures with IFO uptime. The following solution while not perfect is just good enough to get us to next Tuesday maintenance.
1 - Failed supply fan on CER-C5 LHS ISC-R2&R4 +24V is runnning at 90F front and rear, no airflow. The ambient air in that location is very cool, and the current draw is quite low, so we do not expect this supply to trip in these conditions. Fernando noticed that the -24V supply on the same rack is also slightly elevated in temperature and does not have good air flow, so we suspect this supply fan is comprimised as well. Neither of these supplies have had their fans upgraded yet.
2 - Failed supply fan on EX-VDD-1 ISC-R1 +24V 3A was running at 110F front and rear, no airflow. This supply has not had its fan upgraded yet. The PCAL team was using this supply so we could not replace it before close of maintenance window. We applied supplementary cooling to the power supply to see it through until next Tuesday. After supplemental cooling we measured 85F front and 95F rear.
The power supply tray had to be pulled out about 1 foot into the walkway to make space for the supplemental cooling, I placed cones around the hazard, be mindful of the extended rack tray if you do go out to EX berfore next Tuesday.
J. Figueroa, F. Mera, M. Pirello
