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5470Re: WTD: Morrow Wunderbuss Thinker Toys Motherboard Schematic/docs

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  • jack99rubin
    May 9, 2007
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      :
      >
      > Herb/Anyone else..
      >
      > I have a 1977 Morrow Wunderbuss "Thinker Toys" S-100 Motherboard
      with a
      > blown Zener diode near a 12+V position at the back of the board.
      Anyone
      > have a schematic? I checked Herb Johnson's site, there is nothing
      for this
      > board listed. I would like to determine the exact type of diode so
      I can
      > replace it.
      >
      > What would cause a Zener diode to pop?
      >
      > Thanks.
      > Bill
      >

      Being on the digest version of the list, I'm a little slow to get
      messages and being disorganized enough that it took a couple of days
      to find my Wunderbuss manual, I'm a bit slow to respond...I think
      Herb pretty much covered all the relevant points.

      All I can add at this point is that the tantalum caps associated with
      the voltage regulators on this board are listed as 1 ufd on the
      schematic and called out as 20v parts in the parts list.

      Certainly no reason not to go with a higher voltage replacement -
      these guys tend to provide a common source of entertainment on many
      S100 systems and also frequently self-destruct on Heathkit H89
      systems. Yet another good reason to avoid leaning over a vintage
      system when you first power it up after a long rest.

      Always glad to pay my respects to Chairman Morrow,
      Jack
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