§ I am having the same type of issue as ttwiissjeg on 4 different NetVanta 1234 PoE, part number 1702595G1. When it first happened just like ttwiissjeg we assumed lightning strike (All four are in the state of Florida) because of weather in the area, so we replaced the switch and the UPS got everything working again and two weeks later same thing happened except for this time according to the customer no bad weather in the area. I assumed since it was just this one site out of 185 that it was an infrastructure issue at this site grounding, wiring, etc. So we troubleshooted and could find any issues except for no PoE everything else functions properly. Since then we have had two more sites do the same thing none with bad weather at the time. All of these sites have been installed within the past two months and since we have around 180 working properly at other sites I was wondering if there is a known hardware problem (Like a bad batch of switches) or a firmware issue? Any advice would be helpful.
Sorry to hear you experienced the same thing on a much larger scale. It seems too coincidental to lose 4 of them at once, even in your environment which sounds many times larger than mine. My faulty site has approximately 15 ADTRAN devices of various models and I only lost the one that day (no other issues, knock on particle-board-desk-material). I removed my faulty one from production but continue to tinker as time allows as I am not convinced of the lightning strike. It still functions perfectly as a non-POE switch. Never seen anything like it.
I branched this topic to a different discussion. The problem you are describing, if it is not related to environmental issues, may be related to an issue resolved in AOS firmware version R10.5.3. Here is the release note:
Please, let me know if you have any questions about this, or if there is anything I can do. I'll be happy to help in any way I can.