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    Dynaco ST-70 original driver boards - early and later versions - photos ...

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    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Dynaco ST-70 original driver boards - early and later versions - photos ...

    Post by Bob Latino on Fri Dec 19, 2008 12:19 pm

    Dynaco did make an effort to upgrade the cheap brown phenolic board on the ST-70 in the early 1970's by replacing the "brown board" with a much more durable and heat resistant pale yellow fiberglass board. It still had open solder traces but for it's time it was much more durable and a step up from the original brown board. Photos below.

    Bob

    Earlier phenolic board top



    Earlier phenolic board bottom


    Later fiberglass board top


    Later fiberglass board bottom

    fortherecord

    Posts : 3
    Join date : 2009-05-26
    Age : 49
    Location : Rochester, NY

    Re: Dynaco ST-70 original driver boards - early and later versions - photos ...

    Post by fortherecord on Tue May 26, 2009 10:40 pm

    From my experience, the traces on the later fiberglass boards were much more susceptible to lifting from the board while soldering and working on them. The traces are not easy to fix or replace once broken either. However, the fiberglass boards did not tend to develop that waxy or gooey film on them, which the older boards seemed to do. I'm not sure what caused that.

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