No power light, I'd have to guess the power supply has given up the ghost.
Pretty sure Weaknees.com has them, maybe even the TCF Store?
Panasonic Viera TH-46PZ800U 46" Plasma HDTV
TiVo S3-65 HD Hours-Lifetime
TiVo HD 20 HD Hours
TiVo Roamio Basic 300 HD Hours-Lifetime
Harmony 880 Remote Control