combination meter repair - DIY

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Ultanium, Jan 20, 2016.

  1. jerrymildred

    jerrymildred Senior Member

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    There must be hundreds of threads here with that same issue. All have the same solution. Just do what @VFerdman says, and be done with it. This is one of the most common failures on the Gen 2.
     
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  2. lcsjl

    lcsjl New Member

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    Read about the "FOB Trick" here on this tread. Post #13. Just wanted to get more info to see if it was real.
     
  3. jerrymildred

    jerrymildred Senior Member

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    You can always try it.
    Basically, he's just running down the 12V battery a little. I'm sure he could accomplish the same thing by just turning on the headlights and then folding down the rear seats, kicking all four tires twice, and then putting the seats back up. It seems that several people have reported something like, "Hey, everything was fine till I put in a new battery and now my CM won't come on." Seems like when they are on the verge of going completely bad, they will work with a low voltage, but not so well with full voltage. So give it a shot. You won't fix anything, though, unless you replace that capacitor. ;)
     
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  4. VFerdman

    VFerdman Senior Member

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    Here's the thing. When the cap goes bad, it doesn't go completely bad. It just degrades in its value more than the circuit is designed to work with. As we know, it's a 100uF capacitor. I am not exactly sure about the one in question, but most electrolytic caps tend to have +/-20% tolerance to the label. So, it could be between 80uF and 120uf when new. If it degrades below that 80uF the circuit it is used in becomes intermittent. Sometimes it works and sometimes it doesn't. It has exactly NOTHING to do with any manipulations that "seem" to work. It is all 100% coincidental. Those of us who understand electronics (I do) will understand that and those that don't (no shame in it) will convince themselves of some sort of pattern, even though it will never ever be 100% effective (because physics in the electronic circuits). So go ahead and perform the "FOB trick" or any other trick you like if you think it works. As long as the cap is on a hairy edge of working, you will be able to convince yourself of effective trick and even publish it here to help others. But the reality is that the cap is has degraded and will continue to degrade and once it degrades below the point where it will just not work ever, then you'll have to change it. Until then you can entertain yourself and confuse others with "tricks" to solve a problem that can only be solved with one trick. Replacing the cap. Have fun! That's the most important thing in life.
     
  5. OBJUAN

    OBJUAN Member

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    Replace the caps, you'll be GTO
     
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  6. jerrymildred

    jerrymildred Senior Member

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    As it says on the shirt my wife got me for my last birthday (err...most recent. hope it's not my last :LOL:) ...
    engineer t-shirt.jpg
     
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  7. lcsjl

    lcsjl New Member

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    Looks like Mouser and Digikey are both out of stock on the 220uf cap.
     
  8. OBJUAN

    OBJUAN Member

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    #308 OBJUAN, Sep 17, 2021
    Last edited: Sep 17, 2021
  9. VFerdman

    VFerdman Senior Member

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    I find that hard to believe. But even if it's true, these things can be salvaged out of almost any electronic piece of gear with a power supply. Heck, I think most LED bulbs that screw into the regular socket will have one in there.
     
  10. Geoffzie

    Geoffzie New Member

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    That's why I keep a few computer motherboards around ... Lot's of various capacitors and components that can be used on other things!

    I believe the capacitor in the Prius display doesn't go bad because they're defective ... I believe it goes bad because they used an underrated capacitor for the application. Same is true with computers ... Capacitors.will usually last the life of the device ... IF they use the correct capacitor for the application. Although with computers, excessive heat can also affect their life-span as well.
     
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  11. ChapmanF

    ChapmanF Senior Member

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    Between 1999 and 2007-ish (so for much of the run of Gen 2), there was a capacitor plague involving "faulty electrolyte composition". I don't know if any of Toyota's suppliers were involved, but industry-wide it was a known thing.

    Outside of that plague, I've got lots of equipment from the 1970s and 1980s working just fine thanks. :)
     
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  12. Another

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    Many lower end Toshiba satellite laptops a decade ago had capacitor issues in the power supply circuit on the motherboard that render the device inoperable almost always about four years old. Great business model for Toshiba
     
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