Finally got my spare parts for the Raspberry Pi PoE hat and put the ADSB receiver back online. It took DHL Express almost 6 days for the customs clearance, was the last time I used this carrier. UPS is way more efficient on that.
I used the outage for an upgrade to the Mode-S Beast receiver. The performance of the neat little thing is astonishing! Compared to RTL-SDR dongle the ADSB message rate is 3 times higher, I see 40-50 more aircrafts, tracks per hour increased by 300-400, range increased by around 70km and CPU usage is down to 2-3%. That´s with the G7RQG antenna, connected by a short coax cable (<1m).
My dump1090-fa fork now supports the Mode-S Beast directly via USB. See Github for details.
Today, a thunderstorm passing overhead just killed, or better grilled, my ADSB receiver. There was no direct lightning strike but for some reason the DC-DC converter on the PoE hat stopped working and shows a short on the 48V input. The Raspberry Pi and everything else on the 5V side is working just fine. The PoE hat is powered by a 48V switching supply off the 220V mains. That is also still working fine, probably because of its output short circuit protection.
On the PoE hat the DC-DC converter is a Silvertel AG9805-M, ordered some new from http://www.semiconductorstore.com. $8/piece is a good deal compared to the price for the PoE hat or replacement converters supplied by other manufacturers.
I will stock some spares just in case that happens again. But then I need to investigate why that thing breaks.