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5821Re: 1802 oscillator problems

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  • Allison Parent
    Mar 1, 2009
      --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@...> wrote:
      >
      > nils_eilers wrote:
      > > My problem is: the oscillator doesn't run. I build according the
      > > datasheet with 2 MHz Crystal, 10 M Ohm and 2 x 22pF.
      > > Is this a known problem?

      assuming it's wired right and the resistor is indeed 10M (1*10^6)
      ohms the first place I'd go is a new crystal. remember it's a quartz
      wafer in there and it will shatter like glass if dropped.

      Allison

      >
      > Normally, the 1802 oscillator is no problem. Things to check:
      >
      > - what supply voltage? To run at 2 MHz you will need about 5v
      > (not 3v for example).
      > - is the crystal any good? will it oscillate with a regular 4069
      > inverter?
      > - is the 1802 good? You can test the internal inverter that makes
      > the oscillator by just wiring the input high, and seeing if the
      > output goes low, and vice versa.
      >
      > --
      > Ring the bells that still can ring
      > Forget the perfect offering
      > There is a crack in everything
      > That's how the light gets in -- Leonard Cohen
      > --
      > Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
      >
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