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]

23 thoughts on “Fixing the Rovio battery charging circuit

  1. 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. @Mike
    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. 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.

  4. 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.

  5. 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.

  6. 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!

  7. 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.

  8. 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.

  9. 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.

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