Ok I ran the S.M.A.R.T. tests and the first four all said "Passed." The last test (Off-line scan) said "No Start" for primary and "Done" for secondary. I'm not sure how to interpret that.

I ran the overnight test next. It ran fine for a couple hours, then I went to bed. In the morning the TiVo was stuck trying to restart. Should I just run that again?

You should try the kickstart 54 tests. Everything you've said leads me to believe one or both of your hard drives are failing:

http://www.weaknees.com/54

I have the exact problem described in the original post: my Series3 TiVo (TCD648250B, I think) behaved fine for years, then we had a power outage. Ever since, it's been freezing or restarting unpredictably.

I tried the CableCard-related steps in the original post but it didn't help.

Points that may nor may not be relevant:

*The TiVo was in the middle of processing the results of connecting to TiVo at the time the power went out. I was sitting there watching it process the data (last step). It's connected & completed many times since, though.

*I have a WD external expander. Everything works fine though, watching & recording and navigating - generally the freezes and restarts happen when I'm not watching.

*Sometimes the reboot sticks on the "waiting to power up" and I have to unplug/replug to get it to start up successfully. Then it starts up fine.

*When it freezes rather than rebooting, there is often a weird tint to the screen.

Any ideas on the best next step for diagnosing the problem?

Sounds like the external drive is pretty clearly the problem, no? Is it brand new? Have you tested it?

We *constantly* hear of problems with that WD Expander. We use similar internal drives, so we suspect that case is causing problem.

My Tivo Series 3 has worked perfectly for 5 years. I plugged in an unpowered Belkin usb hub (not the Tivo specified one) into the unit in the mistaken belief that I would need a hub to connect a Western Digital hard drive expander (found out about the eSata port too late). After disconnecting the usb hub and all other cables and manually restarting my Tivo, it would power up but then reboot somewhere near the THX screen. I ran the kickstart 54 test and found no hard drive problems. After exiting the test, Tivo continued the startup process and finished. Everything worked perfectly. I then installed the WD hard drive expander and restarted Tivo. It again would restart when reaching the THX screen. I did the kickstart test and Tivo booted up normally. Tivo continues to function normally. I really do not think I have a hard drive or power supply problem. Could it be an HDMI cable issue? Any thoughts would be appreciated.

Excellent! Glad to hear it.

I installed it, and it seems to be working fine again. Thanks for the help!

I'll bet it does - but please post back after you install it.

Yeah, some of the capacitors are bulging. I ordered a new power supply, hopefully that'll fix it. (If it does, it'll be the second time WeaKnees has saved this particular TiVo...)

I'd really just pop the lid and see what there, visually.

Thanks. I haven't opened the box up yet, but I swapped out the cable card that I thought was bad, and it didn't help, so that's just more evidence...

That sounds like a bad power supply to me. See if your power supply has capacitors that resemble the ones in these pictures:

http://www.weaknees.com/bps

I'm wondering if anyone has any input as to whether this sounds like a power supply issue (or at least is likely enough to be that it's worth spending the money on a new power supply instead of just buying a new box)...

Last night, I noticed that two of my recordings were "partial." I then went to live TV and saw that no channels were being tuned (it had the spinning screen saying it's waiting for channel information). I rebooted the tivo, and it came back up, but rebooted itself shortly thereafter, ran for a while, and rebooted again.

I popped out the top cable card, it booted up ok, and seemed to run fine for a while. The instant I re-inserted the top cable card, it rebooted. So I permanently removed that cable card, booted it up, and went to bed. It seemed to run ok overnight.

I'm thinking this might be a bad cable card, but I haven't found any reports of people having cable cards show this particular issue (especially rebooting before it even has a chance to recognize the card and start using it), nor have I seen many cases of cards going bad after working fine for months.

I'll still probably try swapping the cable card, but I'm curious if folks here have any other thoughts.

OK, I replaced the power supply -a couple useful notes for your install page, you need a T8 torx as well for the plug on the power supply, there's six screws (not 2-4), the flat cable doesn't simply pull out, there's a plastic clip that must be unlocked first... other stuff that is easily figured out but the T8 is important and I was lucky it was in the set I had to buy because none of my other sets seemed to have a T10.

The capacitors looked fine, but I was already there and dont have much time, so I replaced it.

The Tivo seems to be fine but then it does go some long time before starting this rebooting nonsense again, I tried your good advice to test the hard drive, but I can not get to the point where I can enter "54". I get the yellow light but only for an instant, not the 10 seconds, and no matter how fast I try to get that 54 in, it just completes the boot

Still, you guys rock. Maybe it is the power supply. I leave tomorrow and will be watching via Slingbox, if it starts rebooting there's nothing I can do

Major thanks for telling me it isnt the Slingbox too.

A Slingbox is not going to cause a TiVo to reboot.

I would suggest you check the power supply for bad capacitors, see:

http://www.weaknees.com/bps

If the power supply looks good, you might want to disconnect the cable from the back of the TiVo to see if the rebooting stops.

You can also test for a bad drive using the kickstart 54 command, described here:

http://www.weaknees.com/tivo-kickstart-codes.php