So, I was rooting around behind the Tivo (a DirectTV standard-def unit that I got from WeeKnees a few years back). I ended up pulling the power cord and putting it back in, when I heard a 'crack' and the Tivo went dead. Uh-oh, NOT good. I really didn't need ANOTHER thing giving me trouble (I was rooting around back there because something else was malfunctioning). And I sure as heck didn't want to be ponying up for a new Tivo any time soon!
Pulled the Tivo and took it to my bench, where it failed to do anything resembling powering up. I tore open the system (the warranty having long since expired), and started poking about. Even with the motherboard and hard drive disconnected, I got no action from the power supply.
I tried probing the fuse with my DMM, but it seemed to be OK. At this point I removed the power supply to see if there was another fuse that might have gone. When I flipped it over, I saw this:
That's the bottom of the power supply and the two lugs soldered in next to the two screws are the incoming line voltage. Notice the blacked bits on the lug closest to the camera. Notice that the solder joint doesn't look all that hot on the other lug.
As near as I can tell, whoever built the supply was a pretty low bidder. They used a line-in connector whose lugs end up in the middle of the holes drilled in the board for them. They then put a skim of solder on there to make the connection. Apparently over the years my plugging and unplugging weakened the joints to the point where they finally failed.
I fixed it by cleaning up the joints and then properly soldering them. After doing that, I plugged the supply in, found it had good voltages, then put the Tivo back together, and it's working great.
I love it when I don't have to spend money!