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Discussion in 'TiVo Help Center' started by johnsom, Jul 25, 2011.
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CraigK, you rock, dude!
Now do the same for the 648 supply.
And any S2s you have handy.
Sorry, don't have a 648.
I was in the process of ordering a replacement fan for a security DVR from Digikey and thought I'd crack open the two HDs we have to look at the capacitors first.
I didn't realize they had different power supplies since I haven't looked inside since upgrading the HDs to 1TB years ago.
My wife's HD (AcBel) looks okay. My HD (3Y) has two capacitors that are bulging (C503 and C504).
Since I had it open to look, I took lots of pictures. Hopefully this visual representation with help folks that run into this thread in the future. My plan is to go back in the threads and find the DigiKey part numbers others have posted and edit the above posts to add that information.
Also while I had the HDs open, I made new truncated copies with WinMFS of the hard drives since we actually got a new software update not that long ago.
Thanks to everyone in this thread who wound up helping me diagnose and repair my Series 3. My symptoms led me here, and I then I found bulging capacitors on my power supply. Rather than figure out how to replace them myself, I removed the power supply and brought it to a local electronics repair shop, where for $45 labor and $9 parts, it was fixed in a day. I'm perfectly happy to pay what I did for a fast, professional repair, and my TiVo is running like it never had a problem.
Special thanks for all the info posted to this thread by unitron and others. I replaced my power supply with one from a used TiVo HD I purchased on *bay and that fixed my problem. I will use the info in this thread to order new caps and repair my original power supply later.
For those of you that do not solder, you should be able to buy a used TiVo HD on *Bay for $30 - 40 shipped. Run it for a few days to make sure it works well and then swap the power supply for your bad one. It only took about 15 minutes for me to do the swap and it was not difficult.
Ask the seller if they've opened up the TiVo and looked for swollen or leaking power supply caps before buying.
And check your local Craigslist.
Replaced bulging 1000uF capacitors in my TivoHD, but still no full boot.
It looks like my power supply voltages are coming in HIGH (about 2x) but I'm not sure I'm measuring correctly. Is there a common mistake I might be making that would cause my measure to be off, or is double voltage an indication of another problem beyond capacitance issues?
Replace ALL the commonly failing caps, not just the 1000uf before trying again.
Common cause of false readings? reading the wrong scale, grabbing the wrong ground point, etc.
I think somebody else had that problem recently and it turned out they had the meter set for AC Volts instead of DC Volts.
Which brings up the fact that checking DC voltages, with the meter on the AC scale, is a way to get a generic idea of ripple, which would indicate there are (still) caps that need to be replaced. If the final output has too much AC in it, and the caps directly feeding the outputs are new, I'd start thinking about the health of the capacitors "upstream" from those. If only one output voltage rail's caps have been replaced, the neighboring other voltage filter caps may not be absorbing as much ripple as needed, and it could be showing up on the voltage rail with new filter caps.
I don't recall what the AC/ripple "cut-off" point calculations are.
I do know, in a perfect world, you would NOT register any AC voltage on the DC outputs of a power supply (or, even a car alternator, which also makes AC then rectifies it to DC, and the car battery is one big capacitor - which can be damaged if the rectifier diodes short/fail, as it can only handle so much AC, just like electrolytic caps).
While filter caps are there to smooth out ripple (which, as stated already, can register as AC voltage), the less they have to deal with, the longer the time until the next failure. Output filter caps that are just old and not working anymore, or working less, can often have no bulging or leaking. Electrolytic caps can dry out without visual cues.
The TiVo power supply should always be tested either connected to the mainboard, or with a simulated load (if you don't trust the PS, or your work done on it). You can damage/kill the PS if powered without load, and the readings will be insanely unstable.
Thanks for all the info you guys have posted. I'm in the midst of repairing my S3 OLED that went down last week. First thing was the 1TB Hitachi I had put in it in 2008 died. Connected it to one of my PC's and verified it was dead (clicking and could not access it).
I had a spare WD10EZEX blue that I restored the image to and it worked for half a day then got the green screen and reboot about every 3-4 minutes. Checked the caps and the 2200uf 25V was bulging so replaced it with a Panasonic today. It now started up and isn't rebooting over and over but is on the green "attempting to fix" for the 3 hours. Possibly the image got hosed or something so I may just pull the drive and restore it again but I may have to just order up a set of caps and start replacing the others. Might as well order some for the HD I have as well but need to open it up and check which PS is in it.
The good news is I was able to use the S3 going down to get my wife to okay ordering a Roamio, which will replace this one when it gets here Tuesday.
Not sure what I'll do with the old unit once I get it repaired but they are all lifetime so it might not be bad to hang onto it as a spare.
EDIT: Well, it repaired fine and appears to be working with the one capacitor replaced. Going through guided setup now.
I have a bad power supply in my tivo series 3 (older version with display). I saw that someone posted on here that they knew a guy in raleigh that would fix it for cheap. I live about 20 minutes south of raleigh, so I would like to get info on this person to fix my Tivo. Thanks!
You've got Private Message.
I have an OLED S3 and it reboots on occasion. Specifically when I attempt to do an transfer via wired Ethernet. I replaced the HD last year, so I do not think the HD is the problem.
Do the caps on this PS look suspect of this known issue. I have not done any work on this PS and the unit is from 2007.
That one in the foreground definitely looks suspect. Any bulge whatsoever warrants replacement. I would replace all the capacitors, actually.
I agree, although the really big one, which rarely fails (enough to cause issues) in TiVo power supplies, has been hard to source for many who have sought out replacements for all.
Unitron is the best source for component replacement lists, in my opinion.
Let's not forget that electrolytic capacitors often dry out, or suffer breakdown internally, operating out-of-spec (under-performing), without any visual cues at all.
Testing for this is possible, but only with the right equipment, and often only with the caps already taken out of the circuit.
At bare minimum, all caps of the same ratings as one showing visual bulging and/or leaking (not to be confused with adhesive used to hold them in place before they are soldered), should be replaced. In the TiVo power supplies, the output rail caps are in parallel, so a failing one stresses the others that have to work harder (or they are all bad, and that one was the weakest link).
Any cap without a perfectly flat top is likely failing. I've had many instances where I spot new ones that are not perfectly flat, on a never-used computer item, and upon applying power, they blow violently and loudly. I've had electrolytic caps violently blow out on video cards and mainboards that were new-in-box and never even had power to them, while they sat in air conditioned comfort for years. This was just recently, and they were genuine Sanyo and other well-known brand caps. My best guess is that they might have lived, and kept living, had I put them into use right away. I back that up with the identical items I did exactly that with, which show no signs of any issues. So, I guess some have a limited non-use shelf life...
Normally I'd be the first one to call BS if I saw somebody else post what I just described in that last paragraph.
I can see by the gray wire that you've got a TCD648250, and there's a list around here somewhere
of the caps that should be replaced on that one.
Basically the very biggest one near the back that's rated at 200V can be ignored, it's not really part of the "switching" part of the power supply and isn't subjected to the stresses caused by handling the much higher switching frequencies.
And the little bitty ones don't handle much current at any frequency, so they're almost certainly still in good shape.
It's the middle sized ones near the heat sinks that should be replaced with known good quality brand low ESR capactitors rated for 105 Degrees Celsius/Centigrade at the correct uF and Voltage ratings.
You've got at least one cap on there that's visibly bulged on top, but just because all the ones that show signs are bad doesn't mean that some of the ones that don't show signs can't be bad as well, so it's "penny foolish but pound wise" to go ahead and replace all of the usual suspects at the same time and be done with it instead of having to do it all over again a few months down the road.
Whether you have a hard drive problem is a separate issue, but you should go ahead and hook it to a PC and run the manufacturer's own diagnostic long test on it (should be available on the Ultimate Boot CD, a free copy of which you can burn) and then while that's running proceed to replace the power supply caps so that you accomplish the maximum while the lid's off the TiVo.
Although it's less of a problem than it was years ago, perfectly decent electrolytics can go bad sitting on the shelf because the dielectric de-forms over time and can't handle a sudden application of full voltage.
Re-forming the dielectric is a lot easier if the cap isn't already installed in something, as you need to put a very low voltage across it and bring that voltage up very slowly.
In your case, what you had may have been Sanyo and other well known brands or they may have counterfeit where some fly by night cap maker slapped bogus labels on something and the next thing you know the entire supply chain is polluted.
I'm aware of the angles on counterfeit caps, more so when it comes to the capacitor plague. I discovered the problem, long before it hit the tech sites and news outlets. I just didn't know the "why" until I saw an article on it.
One thing I'm not sure I made obvious in my post, is that I also had a great many caps that blew in factory sealed boxes, without ever applying any power, or putting the item into use.
I have heaps of "New Old Stock" items that were manufactured a few months before purchase, then I waited years to do anything with any of it, and upon opening the boxes, which were stored at room temperature, all (or most of) the caps were already violently blown-out.
I fully investigated the Sanyo caps and they were genuine ones. They came on a MSI high-end mainboard, and they were the only non-solid caps on the board. That very same board was a P965 board, which had won more awards than they had room to place them on the box. It was nearly every overclocker's dream, and known for stability. I'm apparently the only guy who let it sit around for years, rather than rushing to get it into use. There are no other reports of that happening with the caps. I had six EVGA video cards with other brands of caps which did the same thing.
While I know that the shrink-on label can be counterfeited, I also went to great lengths to verify that every other part of those caps was identical to ones on things I did bring home and use right-away, and have never failed.
I guess the moral of this weird story of mine is that some caps build up gas when they sit around fully discharged, so don't procrastinate. I also am guessing that the cap manufacturers tested every possible parameter, except discharged shelf-life, before shipping their caps.
The ones I really hate, and did it the most, are the ones that a novice could mistake for solid caps, because they look identical, aside from the almost microscopic score-lines on the tops of them. TiVos use a lot of these on their boards, just not on the power supply. I've noticed some TiVos use a solid cap for the cable card slot, while others use an almost identical-looking electrolytic. That got me wondering if the mexicans making the TiVos could tell the difference, and were interchanging solid and electrolytic, which, in theory, could cause issues with the cable card's reliability/performance...
It's not cheap, or easy, to design things that use no electrolytics at all, with emphasis on the cost part. It's also not easy-peasy to substitute solid caps where an electrolytic actually has the best profile (just not the longest lifespan).
Even the solid caps aren't rated to stay in-spec for longer than a typical product's lifespan. They break down too, and likely give you no visible way to know.
thanks for the feedback. yes, it's a 648 model. I'll do the cap job on the PS as needed. When I did the HD last year, I ran all the manf. diags to ensure a good drive. I think the PS is all that needs my attention on this one.