It seems my OTA 4-channel has crashed & likely died. I had the blue light turned OFF, but it came on overnight and will not go offf. I can’t connect to it with any app. I’ve tried power cycling and holding down the reset button for 1 second, 7 seconds, and longer. No change.
Lot’s of devices will go into a crash loop if they don’t have sufficient power during boot up. I can’t say it’s your issue but it certainly is a possibility. Have you tried starting it without a hard drive attached? If the hard drive is using power it can cause a reboot as well. If you have a multi-meter you can also test the power supply. Ideally it should be tested under load. If you know someone with a test power supply you could attach that to the Tablo as well.
EDIT: I usually open up a device and spray it with computer duster as part of the troubleshooting process. Your Tablo is obviously not under warranty after 5 years.
My power supply was behind our TV cabinet. When I pulled out the cabinet, I could hear a slight “squealing” noise emitting from the power supply. Doing a little research, it seems this is likely a “coil whine” or “capacitor squeal”. More likely a coil whine, which is indicative of potential power irregularity. Hence there might be enough power for the blue indicator, but not enough to run the board (as suggested by theuser86 and sodaman_2000). I’ve already ordered a new power supply, so next I’m going to open this one up and have a look, just for fun.