Mac mini video ports damaged, repair?

Hello!

My Mac mini has been doing a great job as a media center and file server on my home. But everytime there is adverse atmospheric conditions (storms with lightning), the video port in use seems to stop working.

It was connected to the TV (a Philips LED with Ambilight, gorgeous!) via HDMI; during one day of lightning the TV suddenly sees no video signal. It never came back, reboots and all, and the TV's HDMI port still works with other devices (so it seems to be a Mac mini problem).

I then used a Mini-DisplayPort to VGA (on the Thunderbolt port) adapter to connect a VGA cable to the VGA port on the TV. It worked, although sometimes I stopped working and I had to reboot the Mac to make it work again. And, guess what, another day of lightning conditions, and the TV suddenly sees no video signal (where have I seen this before?).

Then I tried the last resort, wich I thought would not work (I thought the Thuderbolt port was already "fried"): a Mini-DisplayPort to DVI adapter, then a DVI to HDMI cable, connected to the HDMI port on the TV. It works!

Now, to the point: do you think I should have the machine repaired? It is working now, but I fear if I leave the system like this, it will eventually malfunction again during the next storm with lightning... I may not be home in time to disconnect the machine. By then, this machine will probably not have Apple parts available anymore, so I'll be stuck with a headless server...

And another thing: what do you think is causing the problem? The Mini and all devices on my TV furniture are connected to mains through a Eaton UPS. The network and coaxial cables are a bit exposed (they travel airborne on the outside of the house), could that be a source of problems? Nothing else "burned" on those days, just the Mini's video signal...

Just a curiosity: although the TV gave "no video signal", the Mini detected the TV and adjusted resolution (as seen through remote desktop access). Weird...

Many thanks!