My Series 3 HD (TCD652160) died last night. Started a reboot loop. After I unplugged, when power was restored, the lights on the front panel blinked rapidly (never really coming on) accompanied by a soft click sound. Figured it was the power. I had been running what was a partially recapped 3Y power supply that I purchased from eBay when I started having reboot trouble some years ago. I throught it had been fully recapped, but it turns out that it was only partially recapped (I see that now). Some caps that clearly weren't replaced were bulging now (and I see that those caps definitely had the original factory solder).
Anyway, I still had the AC-BEL power supply that originally shipped with my TiVo and about a year ago, I ordered new, high quality Nichicon caps for it from Digi-Key... all 10 caps... just in case. So I had them on hand and ready.
This afternoon I recapped the AC-BEL... swapped it in and now the Series 3 HD is working again! Note that I have a 1TB WD Black in there that I installed before I ever turned the unit on for the first time... that was back in 2009. It still works great.
Just thought I'd share and say thanks to this forum and some of the posters on this thread for prolonging the life of this Series 3 HD that just won't die.
Note that the feet on the bottom of the unit had completely disintegrated. If you still have an original Series 3 HD, you may want to check yours. Mine were in slimy little pieces (gotta love how some plastic or rubber fails). I replaced the feet temporarily with some dense shipping foam, plastic juice bottle caps and gaffers tape to raise the unit back up a half inch until I can get some new feet for it.