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Series 3 OLED (TCD648250B) Leaky Capacitor

Discussion in 'TiVo Help Center' started by PeteTV, Dec 7, 2013.

  1. Dec 7, 2013 #1 of 13

    PeteTV New Member

    May 6, 2006
    I have a Series 3 OLED (TCD648250B) and at least one of the capacitors (C701) on the power supply is visibly leaking (see attached TiVo-Bad.Cap.jpg ) and I'm in need of some help/advice on how best to fix it.

    Pretty sure C701 has looked that way for several months at least (quite possibly much longer)... I say that because I remember finding it several months ago and making a mental note to look into fixing it. Unfortunately a "mental note" wasn't good enough and I forgot about it. My TiVo decided to remind me by starting a "continuous reboot" cycle. :( Soo... I guess it's time to fix it, but I have a few questions first...

    C701 appears to be the only bad one... I've done a visual inspection (several times) and none of the other caps in the power supply "look" bad... no leaking, no bulging (even subtle), no discoloration. I realize that's no guarantee they're good... just saying none of the others show any obvious signs of damage.

    This post (http://www.tivocommunity.com/tivo-vb/showthread.php?p=9131293#post9131293) lists the specific caps for my model (TCD648250B). What I'm not sure about is should I replace just C701 or should I replace some/all of the others? The person (schoolbus) who posted that list said C401/C402 were visibly bad on his S3, but he went ahead and replaced 11 of the 15. Why not replace just C401/C402? Why replace only 11/15? Why THOSE 11?

    Also, schoolbus's post says it was for:
    Mine is actually slightly older I believe - CP-1104 and SPWR-00008-000 Rev A2. Are those sufficiently equal in terms of the caps to use?

    I also found a nice link somewhere to a project on Mouser Electronics for each of those 11 caps (https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=1a42eea4c1). This will be very helpful once I decide which caps I should replace.

    So... how does one decide which ones to replace? Skill level? Confidence in making the repair? Specific symptoms? History of the TiVo? Age of the Tivo? Random guessing?

    As for my skill/confidence level... well, I'd say my confidence is considerably higher then my actual skill. I'm more then willing to give it a go, but it's been quite a number of years since I've done ANY sort of circuit board soldering (probably high school 35 years ago) and even then it was only the most basic. None then less I'm quite sure I can do it... probably a bit more sure then I should be. :)

    If specific symptoms might help narrow down which caps to replace, I'll be happy to go into more detail. Suffice it to say at this point, I'm fairly confident the continuous reboot is not DIRECTLY related to the power supply/bad cap. I'm pretty sure the rebooting issue is corrupted software. Could a bad cap cause software corruption without damaging the hard drive?

    The S3 was originally purchased back in Oct 2006 with lifetime service (transferred from an S1) and does have a little history in terms of drive replacement and upgrades that I won't go into unless it will be helpful. It's been running pretty much continuously since then.

    Given my over-confidence and lack of skill, it would probably be best just to replace C701, but if there's good reason to replace others, I'll do it.

    As for tools... I have:

    Are those tools sufficient for the job?

    How hot should the iron be... I guess I'm limited to "low" or "high". :)
    Should I get a smaller iron tip?

    I've watched one youtube video about replacing a cap in a tivo power supply and I'll poke around for some others. I also plan to take the power supply out of an old DirecTV receiver that's destined for the recycle yard and do some practice desoldering and soldering.

    Anything else I should need?

    Thanks for any help/suggestions.
  2. Dec 7, 2013 #2 of 13

    dianebrat drastically off narrative TCF Club

    Jul 6, 2002
    There are a ton of existing discussions on replacing the caps in an S3 in the S3 sub-forum, 99% of your questions are answered in them, no need to reinvent the wheel without reviewing them.
  3. Dec 7, 2013 #3 of 13

    nooneuknow TiVo User Since 2007

    Feb 5, 2011
    Cox Cable...
    I agree 100%.

    Just search for "Unitron" & "capacitor". Unitron posts about power supply inspection and repair so much there can't possibly need to be another thread for it. Yet, here we are, with another thread, when about 20 of them exist already...
  4. Dec 8, 2013 #4 of 13

    unitron Active Member

    Apr 28, 2006
    semi-coastal NC
    As long as the thread is already started and I'm sitting here waiting to see if an S2 DT can use a 2TB, or if it'll just go from green screen to green screen....

    You probably shouldn't need to replace the big capacitor that's rated for something like 200V.

    All it has to do is filter 60 or 120 cycle per second ripple out of the high voltage DC that results from the AC being fed through diode rectifiers.

    It's where that high voltage DC goes next that things get interesting.

    Without going into a lot of the theory of how switch mode power supplies work and why they are used, it gets chopped up (by turning transistors on and off several thousands of times per second) into a bunch of pulses at a much higher frequency which are fed into the primary winding of a transformer and said transformer has several secondary windings from which we get lower voltage-higher amperage replicas of that high frequency pulse train. Those have to be filtered into steady DC voltages.

    Dealing with those higher frequencies means capacitors that are charging and discharging several thousand times per second (as opposed to that big one that's only doing it fewer than 200 times per second), and that's where the capacitor's internal impedence (expressed as Equivalent Series Resistance--in other words what series resisitance its opposition to current flow is pretty much the same as as far as the current flow at those high frequencies is concerned) matters when it comes to providing electrical "friction" that generates heat inside the capacitor (which isn't good for the capacitor and which makes it even more resisitant to current flow).

    So the capacitors that have to filter the various DC outputs are the ones that have to work their little electrodes off and are the ones that need to be Low ESR and rated to work at up to 105 degrees C (which is above the boiling point of water).

    Those are the kind of capacitors most likely to break down if made with the incomplete electrolyte formula (the very proprietary secret sauce of which each company supposedly has its own version) that was the result of the industrial espionage that started this whole "capacitor plague" mess in the first place.

    Those are the ones near the heat sinks that are smaller than the big 200V capacitor and bigger than the really little ones.

    As long as you're going to mail order parts and replace one, might as well do them all (of that near the heat sinks group).

    Call it preventive maintenance.

    Besides, just because the ones that bulge or leak can be assumed to be bad does not guarantee that any that are going bad are going to show visible bulging or leakage.

    A year or two ago I replaced two (bulging) caps in an S3 HD supply, resurrecting it.

    Recently I had occasion to open up that HD again as part of some experimentation and troubleshooting on another unit, and discovered that a third cap had started showing the signs.

    I know now that in the beginning I should just have replaced all of the potential troublemakers and been done with it.

    We're only talking about around $10 worth of parts.

    It sounds like you actually have slightly better soldering equipment than do I, except for my 140/100 W soldering gun.

    Get caps that are Low ESR and rated for 105 degrees C.

    The general purpose 85 degree caps at your local Radio Shack aren't really up to doing the job in this particular application.

    Be sure to get exactly the same uF (microFarad) number and at least match the working voltage (V) rating, but if you absolutely can't get the uF you need in Low ESR 105 degree, then you can go one step higher voltage wise, like 16V instead of 10V, 25V instead of 16V, or 35V instead of 25V.

    And take careful note of the polarity of the caps, and don't reverse it.

    The board should be marked with indication of some sort of which is the hole into which the - lead goes, which leaves you with only one choice for the + lead.

    You'll need a #8 Torx bit for the screw that goes into the top of the AC input jack from the outside of the back panel, and a #10 Torx for the ones that hold the board to the chassis.

    I'd use the Kester 44, and while you're mail ordering caps you might want to add in a spool of decent solder wick--the stuff they switched to at Radio Shack a few years ago is absolute crap.

    Take the list offered here and compare it to the caps actually on your board, just in case there was a design change in the later version.

    Whatever your caps are uF and V wise is what you need to get.

    If they made a later change, it might have involved changing something else as well, so you can't assume that going with a different value cap on your unit would be an improvement.

    If your power supply is no longer quite capable of providing enough "oomph" to fully spin up the hard drive, that could cause boot loops.

    Of course you may have power supply problems AND other problems as well, but you need to eliminate the power supply as a possible source of trouble before moving on to other troubleshooting.

    However, while you wait for the mailman, you can take the hard drive and hook it to a PC and see what mfsinfo in WinMFS has to say about it, and you can run the hard drive manufacturer's own diagnostic software long test on it. (and you should do that before putting into service a replacement if it's needed)

    And if it's a WD "green" drive, you can run

    wdidle3 /R

    to be sure that Intellipark is disabled.
  5. Dec 8, 2013 #5 of 13

    dianebrat drastically off narrative TCF Club

    Jul 6, 2002
    Dude you just need it as your sig with amount of times you paste it in the threads.

    (seriously tho, props for doing it)
  6. Dec 8, 2013 #6 of 13

    PeteTV New Member

    May 6, 2006
    First off, let me apologize for opening a new thread if that was the wrong thing to do. I actually did do quite a bit of searching before starting it, but frankly got lost (several times) looking for specific answers. I kept finding bits of partly related info in various threads quite ofter referencing other threads, which would sometimes get me side-tracked onto different aspects of my current issue, then I'd end up with a browser full of tabs and eventually forget what I was originally looking for. Sometimes TOO much info can be worse then not enough. :rolleyes:

    I hoped (selfishly) by opening a new thread I might get direct answers to my specific questions. Again, sorry if that was the wrong approach.

    Thanks very much for responding with very detailed and useful info!!! I have some follow-ups below (if you'd be so kind), but just wanted to thank you up front. If you don't want to answer some/all of the follow-up questions that's fine, I understand.

    This is actually one of the things that got me side-tracked a few times. I'd like to see if I can upgrade to a 2T drive. I've found several places saying you can buy pre-built 2T drives for an S3 (OLED), but only some passing references to diy 2T on an S3 (OLED). I had actually planned to open a separate thread on that subject, but now I suspect that's probably the wrong approach. If you know or can point me to some other threads that say IF and HOW to install/upgrade a diy 2T on an S3 OLED I'd really appreciate it.

    Thanks very much for the explanation... I won't claim to completely understand it all but I think I got the general gist. I do like to understand how things work.

    I had kind of planned to do that, but just wanted a better idea why some caps probably should be replaced and others are probably fine. Thanks again for the explanation. Even though I'll buy all 11 caps, I think I'll start off just replacing C701 and then test the system for a little while before doing them all. C701 seems like it's pretty easy to access whereas some of the others might take a bit more work to get to cleanly.

    Thanks. Any guess what temp I should use... "low" or "high"? Not sure what those translate to in terms of temp or W, I can't find the manual for it. Most of the soldering I've done in the past 30 years has been of the "heat up the big fat wire until the solder melts variety".. ie nothing critical in terms of overheating components, so I generally just put it on high.

    From the Mouser project page it looks like the only one NOT listed specifically as "Low ESR" is Mouser Part #667-EEU-FM0J102 and it's listed as "Low Impedance". I assume "Low ESR" and "Low Impedance" are the same thing?

    I've never used solder wick before. I assume I want something reasonably wide... like .193 and not something narrow like .025? Maybe this Prowick .093 from Mouser?

    I'm pretty sure the 11 caps on the Mouser S3 OLED TCD648250B project match the caps on my power supply. I've already checked most of them... a few are a bit tough to see, but I'll take another look before placing the order to make sure they all match.

    In my case the power supply seems to have enough oomph. Right now I have a different (500G) HD in it and it's working just fine... and this current 500G HD is very suspect... I know it has S.M.A.R.T warnings and plan to replace it (hopefully with a 2T drive), but just wanted to A) verify the reboot problem was NOT the power supply and B) get my TiVo running again... I get all jittery if I go too long without it. :rolleyes:

    The 1.5G WD15EARS drive that was in the S3 when it failed passes brief and full tests via Western Digital Data Lifeguard Diags v5.04f. I notice there's a newer version of the diags (v5.21) on the WD website, so I'll download that and retest.

    I suspect the reboot problem is corrupted software. The main reasons I believe that (and please feel free to disagree) are:

    1. The (WD15EARS) HD checks out via diags
    2. The reboot always happens at the same point about 20-30 seconds after the system is fully up. If it were a power supply issue it seems like the point where it reboots would be a bit more random.
    3. Installing new software (via InstantCake) even with a suspect HD, works (so far - 3 days and counting with no reboot).
    4. I've had this problem before with a different HD which also passes all diags and has since been used on a PC without problems. See this thread from 3 years ago if you're interested.
    Assuming I'm correct (corrupt software), the real question is what caused the software to become corrupt. What I'm wondering, especially since I had the same problem 3 years ago is if the power supply could have somehow corrupted the software. I don't quite understand how that might work, but I've seen references to odd behavior from bad caps. Could a bad cap(s) cause data to be written to the disk incorrectly.... maybe some kind of voltage spike (or something) that messes things up? Something sufficient to screw up the data, but not so bad it actually harms the HD?

    Exactly... based on the fact I've had this problem before, I'd like to at least replace the know bad cap and as you suggest the other potentially bad caps before looking into other things.

    I haven't looked at mfsinfo on THIS WD15EARS, so I'll do that. It's been a while (3 years to be precise) since I've used WinMFS and I no longer have a Windows box, so I'll have to set something up and reacquaint myself. Maybe I can look into creating a Windows XP/WinMFS installation on a USB stick. Has anyone done that?

    And as previously mentioned I have run the WD diags, but will redo it with the newer version.

    It's a WD15EARS and I'm sure wdidle3 /D has been run. See this post (from the same 3 year old thread mentioned above) about halfway through the post where I talk about wdidle3. Nothing has been done to that WD15EARS HD since that time.... well other the diags I ran this time.

    Thanks again for the info you provided and no worries if you don't want to answer any of my rather extensive follow ups.
  7. Dec 8, 2013 #7 of 13

    dianebrat drastically off narrative TCF Club

    Jul 6, 2002
    As long as your S3 has upgraded to 11.0k or higher, you can easily use a 2TB drive.
  8. Dec 8, 2013 #8 of 13

    unitron Active Member

    Apr 28, 2006
    semi-coastal NC
    Okay, baby steps.

    When did your reboot problem start?

    It's possible the drive is screwed up, but it's not impossible that when TiVo pushed the update from 11.0k to 11.0m a while back, something happened that's causing problems when the TiVo tries to switch from the boot partitions with 11.0k to the alternate partitions with 11.0m

    Several Series 2 owners ran into a similar problem on an update to the Series 2 software which came at the same time.

    But it's better not to have a marginal power supply as one of the variables in the equation when trying to figure out what else might be wrong.

    That 0.193" wide wick (which is probably actually 5mm) is a good width for general purpose work. Most anywhere between 1/8th" and 1/4th" would do.

    If it's impregnated with a little rosin flux, that's usually helpful.

    The - lead* of at least some of those caps is going to be connected to ground, which means soldered to a wide area of copper on the underside of the circuit board.

    *negative lead

    Which means that heat applied is going to tend to spread out.

    So the low setting on that iron probably isn't going to be sufficient.

    Generally when soldering and de-soldering you want to get the two things to be soldered together or to be disconnected from each other up to full heat quickly. Adding a little fresh solder by melting it into the joint you're trying to undo when de-soldering can help get the old solder to melt more quickly, partly because of the flux core of the new solder and partly because as it melts and flows it carries heat with it.

    To remove the old caps, probably best put the iron on high and use that de-soldering pump (known in the trade as a solder-sucker) and then go back with the braid (wick) after the cap is out to clean up all the old solder from around the holes.

    Then you can heat up those areas and flow just a little bit of new solder onto them to "tin" them, and that will help when soldering in the new caps.

    You can remove the caps now, which will help in being able to turn them so that you can read them.

    Go find a CVS drugstore and get a dual tip Sharpie (possibly available other places as well, I found some in a Big Lots a few years ago), and use the extra-fine point to make notes on the bottom of the power supply board which holes go with which Cxxx number silk-screened on the top of the board, and which is + and which is -.

    And as you remove each cap, write down, with a regular pen on regular paper, which Cxxx number it was and then put the uF and V ratings next to that.

    That smaller tip on the Sharpie might let you write the C number on the top of each cap in case you need to get a width or heighth measurement later.

    (Why a dual-tip Sharpie? Because the chances that you'll also have a use for the larger tip on the other end somewhere in your life increases the chances of using all of the ink before it dries out.

    Can you tell that my parents grew up during the Great Depression?)

    The capacitor plague problem is much more widespread than just TiVo power supplies (or this free-I got there before the garbage truck-LCD monitor wouldn't be sitting in front of me), and discussion over at badcaps.net seems to generally accept the Panasonic FM series as an adequate sub for FR or FC series in consumer electronics.

    If you're still in the Seattle area you may be able to find a local source for the caps you need.

    What do you have in the way of computers with which to do hard drive work?

    Are still running PCs running Linux, or have you gone over to the dark side (Macs) ;)

    A lot of the tricks I know will require WinMFS which means Windows, but the MFS Live cd v1.4 can come in handy as well, and of course no one should be without the Ultimate Boot cd.

    Once we get your S3 straighened out, as long as it's running 11.0k or 11.0m, you can use WinMFS to prepare a 2TB to go in it.

    I'd recommend the WD20EURS if newegg or Amazon have it on sale some week for under $100, free shipping.

    Just remember, do the expanding as a separate process, not as part of the restore or copy process. And that holds true for MFS Live as well, I suspect.

    I'll let you know in a few days if MFS Live can be used to set up a 2TB for S3 use.
  9. Dec 9, 2013 #9 of 13

    PeteTV New Member

    May 6, 2006
    It just happened on Wed (Dec 4th). I don't recall if I was watching something recorded or live, but the box just rebooted by itself and when it came back up, went through the THX intro, then shortly after rebooted again. I can boot it up and poke around in the UI for 20-30 seconds (haven't actually timed it) and then it reboots.

    This is the same behavior I experienced back in 2010. Back then I didn't know anything about the bad cap issue, so didn't look in that direction. The only "solution" I came up with in 2010 was to reinstall (via InstantCake) on a new drive.

    Sooo... based on my 2010 experience I decided to take a 500G spare drive and reinstall (again via InstantCake) to see if that would work. And it did... no reboots since... I did that on Thu.

    One thing I have NOT tried this time is Kickstart 52 (Emergency Software Reinstall)... it didn't work back in 2010, so I didn't really figure it would work this time either.

    I know I have 11.0m on the drive, because I put it back on the TiVo yesterday (Sat) and booted it up so I could check... I had 20-30 seconds to take a picture of the screen :), but I don't know when 11.0m was first installed. I don't recall seeing any "upgrade" email for a long, long time. Maybe I could call TiVo and see if their records show when I received 11.0m.

    At any rate, if this was caused by an update from 11.0k to 11.0m, then shouldn't there have been an automatic (planned) reboot during the night to do the update? That's not when it rebooted... it was during the day while I was using it.

    Thanks for the tips/suggestions, that will be very helpful.

    I am still in Seattle... and I did look at one place local, but every cap I checked was 4-5 times the price of Mouser, so I'll probably just order from them.

    I'm down to a single Linux (Fedora) desktop and a Mac laptop. But I can probably put together a temporary Win box if I need to. In fact, I'm pretty sure I have a HD with XP on it I can plop into the desktop. Although I'd prefer to see if I can make a bootable USB thumb drive with XP.

    Yes... that USB thumb drive I mentioned already has both MFS Live 1.4 and UBC... along with a few other things.... InstantCake, Fedora Live, KillDisk, I forget what else. A few of them (eg MFS Live) are just the .iso file and the bootloader uses a loopback device to boot directly to the iso. pretty cool. I couldn't get InstantCake to work that way, had to create a separate partition for it.... and I had to slightly modify the InstantCake script so it mounts a partition rather then an entire drive.


    I thought the 2G spare drive I have was a WD, but I just looked and it's a Toshiba DT01ACA200. Do you know anything about that particular model... good/bad as a TiVo drive. I never intended to use it as a TiVo drive, I bought it several months back when it was on sale just as a spare data drive, but if it fits the bill, maybe I'll use it.

    OK... it's been 3 years since I've done anything with either MFS Live or WinMFS, so I need to go back and re-learn the steps.

    Thanks again for all the help.

    PS. I really would like to pull at least the Season Passes off the drive, but based on my experience back in 2010, that turned out to be impossible... or at least impractical. When I used MFS Live (or maybe it was WinMFS) to copy the "bad" drive to a new one it had the same reboot problem. It was only after I reinstalled via InstantCake that the reboot problem went away. So whatever the issue is, it's preserved in the backup copy. I haven't tried that this time, so I can't be certain it will behave the same.

    Hmm... I do have a backup copy I just found that was made AFTER installing via InstantCake and then forcing an upgrade (from 9.2) to 11.0h. I don't recall if that was made after I'd redone most of the Season Passes or not. I may try to restore that to a different drive and see what's in it.

    PPS. One problem I have (in terms of testing) is after installing via InstantCake on my 500G drive, I had to call Frontier and have them re-pair my cable cards. Now if I try to boot the "bad" (1.5T) drive or (I assume) any other freshly installed drive it will screw up the cable card settings. I assume it must be writing something to the cable cards and/or transmitting something to Frontier. I already did this on Sat about an hour after I called Frontier. Had to call them back and redo it again. Luckily it went very smooth both times.

    At any rate... if I remove both cable cards and/or disconnect the cable before I install a different drive (for testing purposes) will that be enough to prevent it from screwing up the settings in my current working (500G) drive?
  10. PeteTV

    PeteTV New Member

    May 6, 2006
    I haven't ordered my replacement caps yet because I wanted to measure the existing ones to see how they compared to the Mouser S3 OLED TCD648250B PSU Caps project.

    I've taken pretty good measurements using a micrometer and it looks like a few might be a bit tight, they're 2-2.5mm larger in diameter. C601, C502, C501, C504, C503, are all 10mm on my board and the replacements are 12.5mm. C403 is 8mm on my board and the replacement is 10mm.

    The group of caps consisting of C601, C701, C502, C501 and C504 *looks* like there should be enough space, but they might be touching each other. Right now they're sort of bent towards each other, so I think I can separate them a bit more.

    C503 and C403 are little more worrisome... mainly C503 which is between a jumper (JP105) and a little springy-thing-a-ma-bob (L500), with C403 pushing in on one side. There's only about 1mm between the side of C503 and L500 and 1mm between the other side of C503 and JP105. If I go from 10mm to 12.5, the cap will be right next to both... possibly a bit overlapping JP105.

    Soo... is it important the sides of the caps don't touch each other?

    What if C503 touches L500 (the springy thing) and/or gets too close to JP105? Doesn't seem like that would be a good thing.

    Right now there's some white silicone like caulk between some of the components and/or the board. Appears to be either helping to hold the components to the board and/or prevent them from touching nearby components. I'll have to remove most of this to get the caps out, so it won't be of much use. Is there a suitable replacement for this stuff?

    A few details (these are from my board):
    • TiVo PN: SPWR-00008-000 RevA2
    • Board: CP-1104
    • C601: 2200uF, 16V, 10mm x 30mm
    • C701: 2200uF, 25V, 13mm x 29mm
    • C502: 3300uF, 10V, 10mm x 25mm
    • C501: 3300uF, 10V, 10mm x 25mm
    • C504: 3300uF, 10V, 10mm x 25mm
    • C401: 2200uF, 6.3V, 10mm x 20mm
    • C401: 2200uF, 6.3V, 10mm x 20mm
    • C503: 3300uF, 10V, 10mm x 25mm
    • C403: 1000uF, 6.3V, 8mm x 15mm
    • C603: 470uF, 16V, 8mm x 20mm
    • C702: 470uF, 16V, 8mm x 20mm
  11. unitron

    unitron Active Member

    Apr 28, 2006
    semi-coastal NC

    A suitable replacement for the white stuff is probably air.

    I'm pretty sure it's mostly there to hold stuff in place while it's wave soldered from below.

    (There's a "sea" of molten solder and the board is held right above it and a wave is generated that raises "sea level" enough to solder all the connections on the bottom of the board at once)

    L500 (and other components which have names starting with L as far as what is silkscreened onto the circuit board in which they are mounted) is an inductor.

    I'm pretty sure the L comes from early days when it was noticed that putting one or more "loops" into a wire changed the characteristics of a circuit.

    L500 is a coil of wire because coiling it like that gets the magnetic field around each turn to re-enforce the fields around the other turns, which is how you get the desired quantity of the desired quality of inductance into a relatively small space.

    The wire used has a "varnish" type insulation, just like the wire used to wind electric motors and guitar pickups, so that the turns don't short together electrically.

    This insulation also protects L500 from shorting to a capacitor's outside can, so if they touch it's not the end of the world.

    Without opening up a 648 to be absolutely certain, I'm going to assume that JP105 is a bare wire "jumper" that connects two places on the bottom of the board by way of the top of the board.

    If there's a bare wire, it doesn't need to be touched by anything not insulated.

    The outside of the cans the caps are built into are usually covered with plastic or paint or something non-conductive, but play it safe if contact is possible and lay a little electrical tape over the top of that jumper.

    I recommend Scotch 33+.
  12. verok1

    verok1 New Member

    Aug 5, 2014
    For what is worth, I had difficulty finding this info in the forum w/o confusing edits and this thread proved very useful to me.
    Now I'm digging on the mentioned previous posts to find tips on soldering.
    Thank you UNITRON!!
  13. unitron

    unitron Active Member

    Apr 28, 2006
    semi-coastal NC
    If you really want to thank me, keep the name uncapitalized--it tickles.

    If you're talking about soldering/unsoldering on the bottom of the TiVo power supply circuit board, use something rated at least as high as 40 Watts, melt a little new solder into the old solder to get it to melt so you can remove the old cap leads, then heat the new cap lead and the copper around the hole until they, and not the iron, melt the new solder when soldering in the new caps.

    Use rosin core (not acid core) solder that is only an alloy of lead and tin, with no other metals. Either 60/40 or 63/37 should work okay. Get some that's about as big around as a toothpick or a hair smaller.

    If the budget is tight, the Radio Shack 45W de-soldering iron (looks like the love child of a soldering iron and a turkey baster) can also heat up the work enough to melt the new solder when installing the new caps.

    Don't forget the one little screw that goes into the top of the AC input jack from the outside back panel of the TiVo when taking the power supply board out.

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