I've encountered a strange problem with two different 6509s - for no reason we can trace to date, one of two 3000W power supplies running in redundancy mode will fail and the 6509 (dual sup720-3B) will start a reboot loop. While there are six of these configurations in service, all running 12.2(18)SXF7, only two have shown this symptom. One power supply was on straight building power, the other has been on building and UPS. Non-E chassis, high speed fan trays. There are no alarms in the logs from when the PS fails and the switch is usually rebooting or locked up so I can't get a sh tech, sh power, sh anything off it for diagnostics when it happens. For one switch, the outage has happened twice, on a weekend.
Has anyone else seen this?