If you suspect that the power supply on your Tablo OTA DVR has failed (or your cat decided to use it as a toy) you can purchase new ones via Tablo's online store.
Tablo Replacement Power Supply - United States
Tablo Replacement Power Supply - Canada
These replacement power supplies are compatible with Tablo 2-Tuner, Tablo 4-Tuner, Tablo DUAL 64, Tablo DUAL 128GB, Tablo QUAD, and Tablo QUAD 1TB OTA DVRs.