Fixing the Rovio battery charging circuit

[Chris] was unhappy with the battery performance of his Rovio. It seems that he’s not alone, so he set out to reverse engineer the battery charging circuit to see if there was a fix. Boy is there, what he found is the diode above, apparently installed backwards when compared to the silk screen diode symbol. Now it’s entirely possible that the silk screen is wrong and this was fixed during assembly. We think that’s unlikely because if the closer of the two diodes was supposed to have the same polarity as the one next to it there should have been room to install them both in exactly the same orientation. [Chris] pulled out a soldering iron and changed the diode to match the silk screen. That fixed his problem and he’s now getting better performance than he ever has.

[From our comments section]


  1. Mike says:

    Ha, nice catch. Even knowing what to look for, it still took me a second, since the “long leg” is reversed from the other diode also.

    I guess the markings really are useful, eh?

  2. Digital says:

    that’s why the boards are marked out.

    I recently had to replace some caps on an older mainboard… the polarity is marked out on the board so that you can’t really screw up (as long as you know how to read the thing).

    I also love just looking at pcb board layouts to see if there is maybe something that isn’t on the board that there is room for. Can’t tell you how many times I’ve added things like extra usb slots to computers because the board was pinned for it but wasn’t put on because it was the lower end model of the same product line.

  3. Pilotgeek says:

    Epic fail on the manufacturer’s part. Nice catch.

  4. fartface says:

    Anyone have a fix for the crappy motors and wheel gears? I have one dragging more than the others so forward is more of a drunken slide to the front left.

  5. KingofPain says:

    Awesome fix! I’ve already dropped $$ for another battery ’cause I thought that was the culprit. Gonna check this out as soon as I get home.

  6. cgmark says:

    Parts like those are usually hand assembled so probably worker error. If that went to an AC power source then like it was installed it would have delivered half the power it was supposed to. It would have worked as a quarter wave AC – dc conversion instead of half wave.

  7. TheMoogle says:

    I wonder if they will issue a recall now?

  8. cde says:

    @ Fartface, weigh down the right side?

  9. HackJack says:

    Thumbs up for Chris. Thumbs down for Rovio engineers and Q/A.

  10. Bill says:

    Well that’s why they were on Woot for $100 a while back. I bet the manufacturer found the problem and sold off the lot as surplus.

  11. walt says:

    nice! too bad I gave up on mine last year and returned it. no $$$ for you wowwee cause you effed up and didn’t fix it!

  12. Davo1111 says:

    wow, fail on manufacturers part

  13. Knuckleball says:

    Oh Rovio,,, *Price is right failure horn*

  14. mlseim says:

    Wait a minute …

    Look at the silkscreen closer.
    Notice the -|<- Symbol.

    The line on the diode should be on the line-side of the silkscreen.

    Now, it's backwards as shown in the photo.

    What they did was installed it correctly as in the polarity, but put the long lead on the wrong bend, so it only appeared to be installed backwards.

    The diode correctly installed has the short end on the same side as the line on the diode. Both diodes should have had their leads bent and
    cut the same way, but they didn't.

    They did install them correctly though, according
    to the silkscreen … until he reversed it.

  15. mlseim says:

    Nevermind my previous post.

    I thought the photo was AFTER he reversed it!

    The photo as shown must be the diode BEFORE he reversed it. my bad.

  16. Justin says:

    Think I can guess where these were manufactured…


  17. strider_mt2k says:

    Yeah that was a boo-boo alright.

    Very cool that it has been found and fixed.

    Well done!

  18. JB says:


    Didn’t see the video, but wild guess….China?

  19. freddyb says:

    I pulled apart my Rovio (purchased from the Woot deal) last night and discovered that the diode is correctly installed in mine.

    The battery life has been pretty poor from day one and the Rovio is basically unusable for more than a few minutes today.

    I was very hopeful that this post would lead me to a solution, but unfortunately this is not the cure in my case.

  20. keng says:

    hmm odd,,, that diode is missing in my unit ??

  21. tony says:

    i have just unscrewed my rovio and seem to be missing one also shock horror

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