Fixing failed TiVo

**CheshireCat** · 09-01-2012, 02:16 PM

So, my bedroom TiVo has failed -- stuck on the "Starting" boot-up page.

Given that I can pick up a brand-new one for NZ$200 it was easy to just replace it, but I want to fix it! So, here is a summary of what has been done so far.

1. Open the box. This needs a Torx T10 screwdriver, so no real problem there.

2. Test the hard disk. Problem of this nature is apparently most likely to be either Hard disk or Power Supply related.
I take the disk out of the box, and connect it to my Windows PC (which uses SATA so it has the same interface, luckily). Using WinMFS (free download) I can verify that the disk is readable, and can take a backup of it to show it does not have bad sectors. At this point, I could replace it with a larger disk (restoring the backup and extending, using WinMFS) or else completely restore a copy of the factory-default image (Ive downloaded a copy from elsewhere). However, disk looks OK, so on to the next cause.

3. Check power supply. Look for any leaking or bulging capacitors (check for domed tops) or obviously failed components. None apparent (the white blobs are glue, not leakage). However, there is a quiet 'tick,tick,tick' coming from the power supply, which is a capacitor discharging and recharging as the power supply attempts to boot the voltage regulators. So, we've proved the problem lies with the power supply! To remove the power supply takes a T10 torx for the main scres, and a T8 for the single screw on the external connector. I cheat with this by using pliers though, as I dont have a T8.

3. Replace failed capacitors. This would be easier if there were any obviously failed. However, research indicates the most likely to fail are C501 - C504, the four 2200uF/10V capacitors. 10V tolerance is a bit low, so buy a new set of 2200uF/16V which should last longer for a massive 80c each from Surplustronics on Queen St.
The other ones likely to fail are the 47uF/50V capacitors C801 and C113, but the nearest match I can find is 47uF/160V which is acceptable but about twice the size! They're only 20c each so I get a couple anyway and will try these next. I'll do the 2200uF first, andif they dont fix it, I'll try replacing the 47uF (some posts indicate that the 'ticking' problem is more likely caused by the 47uF capacitors).

I will post after I try the replacing of capacitors. Also, I have some pictures.

**Darren King** · 09-01-2012, 09:35 PM

If your TiVo is on the initial boot screen then it is not reading the hard disk. That screen is embedded in the mainboard PROM. Try it: remove the hard disk and power on again and observe what happens. The TiVo should attempt to reboot after about every 30 seconds and return to this screen. Given you have two others (as per your signature), why don't you first try and exchange a hard disk temporarily to test this?

The "tick tick tick" power supply is normal if you have disconnected it from the mainboard and hard disk. It needs a load to function. You can simply plug the hard disk only back in and verify it starts, and then verify you have roughly +5VDC from the red wires and +12VDC from the yellow wires with respect to the black wires. Given you still had the "welcome" screen I do not think power supply is your problem here. Although your comments about failed capacitors is valid, that is extremely rare with the S3 power supplies.

**CheshireCat** · 29-03-2012, 07:29 AM

Update -- I managed to fix it in the end!

I swapped out the 10V 2200uF for 16V 2200uF (all 4 of them in one go) and this solved the problem. Although none of them appeared bulging, various things I've read on the internet seemed to indicate that this was the sort most likely to fail due to the low voltage tolerance range, and it certainly seems to be true in this case.

Opening the box and removing the power supply was easy; desoldering and re-soldering the capacitors was a little more tricky but no real difficulty as I've done soldering before. The big win was ending up with $200-worth of TiVo operational again, so a 3rd TiVo for our house to go in the kids' playroom.

2012-01-08 14.04.40-s.jpg
The power supply board removed
2012-01-08 14.05.530-s.jpg
One capacitor desoldered. Make sure that the -ve of the new capacitor goes in the correct hole (on the shaded side of the circle)!