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    Dynaco FM3 Update

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    Peter W.

    Posts : 1003
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Dynaco FM3 Update

    Post by Peter W. on Mon Apr 02, 2018 12:29 pm

    On Saturday afternoon, and after finishing the minor refurbishment of an HK Citation 17, I decided to dig a bit into the FM3 I snagged a few weeks ago. I have the new filter caps (restuff-size) in hand, and have ordered the new PEC modules. Interesting preliminary finds:

    a) The solder throughout is very brittle, and more-or-less powders upon heating. So, quite heavily oxidized.
    b) There is a thin layer of grease throughout, combined with the skunge that sticks to it. Either a smoker, or a greasy environment, or both. In any case, this one looks like a candidate for an industrial degreaser - suggestions welcome!
    c) The line-cord connections (cord was cut) were so oxidized that merely pulling on them caused them to fail.
    d) The line-cord was installed through a grommet, not a strain-relief.
    e) The wiring, though generally neat, shows evidence of haste.

    Accordingly, I am going to have to retouch the bulk of the solder connections, adding fresh solder. Especially those subject to mechanical movement or heat. The 200-watt soldering gun will be useful for those several chassis connections!
    I will install a new polarized line-cord and the correct strain-relief.
    Replace any dubious parts in addition to the PEC modules, key capacitors and key resistors.
    All the tubes check high in the GOOD range, so they will do fine.
    Refinish the top - rust and old paint removal, new paint.
    Full alignment thereafter.

    Total estimate, about 5 hours and $65 in all. Not bad for what will be a working unit in reasonable cosmetic condition when complete. And excellent therapy!
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    peterh

    Posts : 1068
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Dynaco FM3 Update

    Post by peterh on Mon Apr 02, 2018 1:31 pm

    The FM1/FM3 has space enough for an IEC intake. Just enlarge the existing hole and all future
    powercord problems are solved.
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    Peter W.

    Posts : 1003
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Dynaco FM3 Update

    Post by Peter W. on Mon Apr 02, 2018 2:37 pm

    peterh wrote:The FM1/FM3 has space enough for an IEC intake. Just enlarge the existing hole and all future
    powercord problems are solved.

    They do. But, a replacement UR-certified polarized plug & cord costs me a princely US$2.29 including taxes, and does not void the UL rating as would the IEC modification. I stock the strain-relief devices. It is fused with the correct dual-element fuse as well.

    Note that from where you are this may seem persnickety - but should there be an 'event', my insurance company would not have an excuse to refuse coverage. And, yes, they would do so were I to knowingly modify the chassis as you describe and there be a large claim arising therefrom, even if not due to the modification. How do such things work over there - what happens if you take a vintage item, or one from over here, for instance, and modify it to current Euro standards, should there be an issue?

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    Re: Dynaco FM3 Update

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