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Thread: Victory! Sol-20 repair

  1. #11
    Join Date
    Jan 2007
    Location
    Pacific Northwest, USA
    Posts
    25,203
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    "Mylar" is a trademark by DuPont for Polyethylene Terephthalate (PET) film. Most non-infringers generally call it "polyester" or sometimes just "polyethylene".

    For example: this.

  2. #12
    Join Date
    Nov 2012
    Location
    Richmond Hill, Ontario, Canada
    Posts
    883

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    Quote Originally Posted by falter View Post
    Question.. I am looking around for 'space blankets' here in town to get my keyboard repaired.. none are made from mylar... they all appear to be aluminized something or other now.. will that work? Or does it have to be mylar?
    Try Dollar Store metallic looking wrapping paper.

  3. #13

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    I wrote up details of the Sol and a summary of my repairs in case this helps anyone else:

    https://sites.google.com/site/retroborkenwerk/sol-20

    https://sites.google.com/site/retrob...basic-function

    I haven't had a chance to test the foam inserts for my keyboard yet, but if they work, I'm happy to share my now seemingly lifetime supply of metalized Bo-PET film.

  4. #14

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    Keyboard repaired.

    However, had my first tantalum 'splode testing a RAM board in the machine. A good pop and small flame. I had tested for continuity / resistance, but that wasn't enough.

    One culprit may be the voltage going to the cards. The unregulated power on the Sol expansion card seems to be running high. I measure 11V on the 8V line and 19.7V on the 16V line (-19.5 on -16V line). The voltages on the regulated outputs seem to be fine.

    Any tips / thoughts?

  5. #15

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    Can you check your transformer for a "4 3991" marking? If it has that you need Change Notice #9 from here. Otherwise, something bad is going on in the power supply.

    Since it's unlikely you'll find the parts needed by CN9 (if you need it) you might begin thinking about some switchers.

  6. #16

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    It's the T2 transformer. I'll go in at some point and double check the transformer connections. Otherwise, not sure what could have gone bad. The circuit is just the transformer, rectifier, smoothing cap and bleed resistor.

    The Sol and DRAM board are working fine, but 11V on the 8V line is towards the upper operating limit of the 7805 regulators. It could come down as I add more cards.

    Does anyone else have measurements of their Sol PSU outputs, especially on the unregulated side?

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