Substitute capacitors

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  • joecb

    US Member - 2 Years
    Replies: 739
    Topics: 76

    Starting a new thread…. Tubs wrote ..

    “They came from eBay. Got them to substitute the condenser in a poinion
    as has been a topic here from some time. They didn’t work. Went back to
    condensers as I know what to buy.”

    Tubs, I know that you are really good about working “fixes” out to final results, so what is with this “did not work” ?

    I have had great success with substituting metal foil caps for the old paper capacitors. I have friends the swear by the substitute ,claims they will fix any ill magneto.

    We use the Vishay #1839 HQ .22mf  850 Volt metal foil caps.  I have found that .22 mf to be just about a universal fit.

    Joe B




    US Member - 2 Years
    Replies: 1963
    Topics: 29

    when I use caps I use at least 600v minimum.


    Canada Member - 2 Years
    Replies: 3174
    Topics: 302

    I purchased theseto refill  cans   as per M.Mohat process.   I  haven’t tried them in real life but they are rated 630v

    Cary 10pc Metallized Polypropylene Film Capacitor 0.22uf 630v for Tube Amps : Tools & Home Improvement

    Joining AOMCI has priviledges 🙂

    The Boat House

    Replies: 4192
    Topics: 104

    Responding to Joe B. I was acquiring a lot of Super Elto’s and
    they all need the wiring repaired. The coil and the condenser
    are in a tube filled with tar. I had figured out how to get the coil
    out, clean it up and reuse it but the condenser needed to be
    Its value is .1mf. I stumbled on to these. They exceeded the 600
    volts that was being recommended. I posted them on the board
    and asked if they would work before I ordered them and the
    response was, they would.
    When I tried one of these 1mf caps. I bench tested the assembly
    before I filled the tube with wax. The coil would fire on the bench
    but the motor wouldn’t run.
    I took the coil out again and replaced the cap with a condenser
    and it took right off.
    Posted my experience and Tom Manley had an explanation that
    made sense to me. He said – that condensers have a dV/dT
    specification. Dumbing it down for me, the condenser wasn’t fast
    enough. That would coincide (in my mind anyway) why it would
    fire on the bench but motor wouldn’t run. He gave what the min.
    spec. needs to be, and I have it some were, but its something you
    would have to search out before you buy.
    So its more than just the mf value and the voltage.
    Now that I throw the original coil away and use a substitute who
    knows what the correct condenser value would be. I have a few
    that I favor but its more about how the fit. I can get most of the
    ones I prefer at any auto parts store.
    It was expanded to me that having the wrong condenser value can
    accelerate the point wear but other things can change the actual value
    at the points like, the length of the wire, poor connection at the wire,
    or a poor ground. All can cause the points to pit prematurely but as
    little as these motors get run you probably never notice it. So far that
    has worked for me and I believe I run my motors more that most.


    US Member - 2 Years
    Replies: 608
    Topics: 53

    Per Mr Mohat’s suggestion, I also tried these ceramic capacitors:

    Murata KRM55TR73A224MH01K

    This particular number is 0.22 uF, but the are available in 0.10, 0.15, and 0.33 uF also.  I am unable to find the dV/dt rating for these capacitors.  They are a little less than $3 each.  You need to solder leads to them, but they are very small and can be used to rebuild all sorts of condensers.  The ones with the brass cans, like WICO and some used on Mercury MK motors are really easy to do.



    Canada Member - 2 Years
    Replies: 3174
    Topics: 302

    I have some of those  small ceramic caps … got to find them in the bin somewhere 🙁   and try them out

    Joining AOMCI has priviledges 🙂


    Replies: 5696
    Topics: 296

    Just a word of caution here but beware if buying capacitors or any electronic components off Amazon or that big auction site as they are well known for selling fakes cleverly disguised as being genuine. It’s always best to spend a bit more and purchase from one of the major suppliers such as Mouser, Digi-Key, or Newark etc. That way you know you will be getting the real McCoy and not a counterfeit dressed up to look like the original.

    Also, study the data sheets for the capacitors as some of them are SMD’s (Surface Mount Devices) and can be extremely small requiring special skill and equipment to install them.




    Canada Member - 2 Years
    Replies: 3174
    Topics: 302

    nothing new under the sun… remember those early   5-6 -7 transistor radios  with most of the transistor legs all soldered under the board… yes the radios had 5-6-7 transistors

    Joining AOMCI has priviledges 🙂


    US Member - 1 Year
    Replies: 479
    Topics: 41

    See this thread:


    The Vishays work well.


    Replies: 5696
    Topics: 296

    Another thread about the Vishay caps.

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