Service connection lost.

Hi all, I have 4, Series 3 HD TIVO's all connected to the same network, some hardwired some via wifi. One TIVO (No3) constantly loses connection (no program information available) to the TIVO service every 2 or 3 days. I have moved it to different locations and tried direct connection and wifi connection but it does not make any difference. It still loses its connection. It reconnects OK when I go into ‘network’ and start the reconnection process. I have been through the forums and see some have trouble with routers and wifi but none with hard wired connections and none with only one TIVO out of 4 with a problem. It has had its HDD drive replaced a couple of years ago after it started rebooting regularly and has been OK in that regard since. This problem started about 3 months ago and is very annoying as it will miss programs when it has disconnected.
Do you think it could be a HDD problem again, software or power supply problem? Any help much appreciated