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For Your Use: A full lis of capacitors needed for Electone power amplifier (PU) board

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  • For Your Use: A full lis of capacitors needed for Electone power amplifier (PU) board

    I am in the process of (I hope) repairing the PU (power supply and audio amplifier) board of my Yamaha Electone EL87. The PU board is the same for EL90, EL70, EL87, and perhaps some other models. I have compiled a complete list of all electrolytic capacitors on the board, including physical dimensions (enclosed). This should be of help to anyone who has to replace capacitors on this board. Enjoy!
    Attached Files

  • #2
    Good work !

    Maybe add the lead spacing when you get round to doing the work? Alternative manufacturers may have differing dimensions.

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    • #3
      Just a follow-up. The replacement of the capacitors was successful.

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      • #4
        Thank you for that list pieanoman ! I've got two EL-25s, and so far I have not had this issue with either one, but have saved your list just in case.

        I am thinking that Yamaha probably used that same PU in all the spinet EL series - they tend to use standard components in each series / era, just like many other Mfgs do in their products. That keeps the R&D costs down some by not having to design and build a PU for each individual model.

        Regarding capacitors in general, I have found that some on here are really quick to suggest replacing them All on any older organ. A lot of times that is rather overkill. In this case though it seems to be what we in the mechanical repair world call a Pattern Failure. As in, if it is from that era, it Will eventually have this issue. And it will have the issue long before other organs made in the same time frame have any problems.

        I think this era is also the time frame where certain Dell computers had a rash of failed motherboards due to leaking / bulging capacitors. If I am recalling correctly, that was caused by a bad batch of capacitors from the Mfg. Not sure if it was Nichicon, but that name does stick in my mind. I'll bet Yamaha got a truckload of bad ones too.
        Regards, Larry

        At Home : Yamaha Electones : EX-42 ( X 3 !!! ), E-5AR, FX-1 ( X 2 !! ), US-1, EL-25 ( Chopped ). Allen 601D, ADC 6000D. Lowrey CH32-1. At Churches I play for : Allen Q325 ( with Vista ), Allen L123 ( with Navigator ). Rodgers 755. 1919 Wangerin 2/7 pipe organ.

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        • #5
          Originally posted by Larrytow View Post
          I think this era is also the time frame where certain Dell computers had a rash of failed motherboards due to leaking / bulging capacitors. If I am recalling correctly, that was caused by a bad batch of capacitors from the Mfg. Not sure if it was Nichicon, but that name does stick in my mind. I'll bet Yamaha got a truckload of bad ones too.
          See the link below about the rash of "bad" caps . . .

          https://www.badcaps.net/index.php?pageid=causes

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          • #6
            This also...

            https://en.wikipedia.org/wiki/Capacitor_plague

            Geo

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            • #7
              Bingo, that's it!

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              • #8
                Interesting to read about this. I've been gradually servicing my collection of 1970's equipment much of which has amplifiers and thankfully no problems. It seems amazing to hear of organs such as the EL90T I loved would eventually fail bearing in mind the massive cost of the instrument although I have always felt tech has always had a inbuilt time bomb to make you buy another product. As far as I know the new owner of my much loved EL is still enjoying it but it goes to show no mater how much you look after something dust cover etc, inside the works something else could be going on without you knowing it. A wonderful instrument that EL90T and I still miss it.
                HAMMOND XE200 Special Edition

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                • #9
                  Hi Larrytow. Yes, Yamaha apparently reuses boards quite a bit. I'm working on an EL-900 right now. It has exactly the same PU board as the EL87 and EL90, but many of the functions of that board are moved to other boards (meaning the PC board is identical, but many of the parts installed in other models using the same board are missing). On the EL900, the PU board provides audio amplification, but most of the power supply rectification, regulation, and filtering is done on other boards.

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                  • #10
                    Pieanoman, thank you for providing the capacitor document. It was very helpful and saved me a lot of time. I did find one capacitor on my EL-90 PU board that is not listed in your document, possibly due to a difference between the EL-90 and EL-87. In case you want to add it to your document, the extra capacitor on my EL-90 PU board is C221, which is a 100uF / 16V cap, identical to C218.

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                    • #11
                      Glad to hear it's helpful. Yes, I'll add it to the list (it may take a bit of time, as I'm traveling right now). Glad that you're preserving your EL-90!

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                      • #12
                        After reviewing my work, there are actually three capacitors on my EL-90 that are not in your document, probably due to the slight difference between the EL-87 and EL-90.

                        They are:

                        C221: 100uF 16V
                        C313: 10uF 16V
                        C332: 1uF 50V

                        I noticed that C327 is listed twice in your document.

                        Also, I figured out that the codes on the capacitors are date codes.

                        For example, your C223 and C224 capacitors coded with H9746 indicates that they were manufactured in the 46th week of 1997.
                        My C223 and C224 are stamped H9132 which means 32nd week of 1991.

                        Thanks again for taking the time to provide this useful document.

                        Unfortunately, my EL-90 has a new problem, which I will post in a new thread.

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