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900New boards

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  • scott@opentrac.org
    Sep 4, 2006
      The Proto C boards check out OK so far - the firmware's slightly different
      to accommodate the ST202 chip, but it should be transparent to the user.

      I've built three T2-135 boards (the Alinco DR-135T internal version) and so
      far they all work - no sign of the oscillator problem the last SMT board
      had. I've got a picture of one installed at
      http://n1vg.net/images/t2-135.jpg.

      So far, they're working pretty well. I've noticed a couple of problems that
      seem to be in the DR-135 and not my board. For one, when it's in packet
      mode the audio is muted, but the speaker still pops every time the squelch
      opens. Turning the volume down fixes it. And when a GPS receiver is
      plugged in to the front panel jack, it gets crosstalk into the speaker audio
      and you can hear digital noise that's independent of the volume setting. I
      have no fix for that so far, though in a car you might not notice. Both
      problems are still present even when the board's not installed, and I'm
      assuming it's the same for the EJ41U.

      For future revisions, I'll probably swap the pins on CN1 so the connector
      can be mounted on top. Unless I can get the proper connector from Alinco,
      anyway. The Molex connectors are backwards because they're not supposed to
      be through-hole connectors - they're supposed to be vertically-mounted and
      surface mount. The work well as right angle through-hole connectors, albeit
      with the wrong orientation. The JST connectors come in R/A THT, but they
      don't mate well.

      Lots more tuning to do still. The 135 board also has a pre-emphasis filter
      network, since the radio apparently doesn't provide any. I really need to
      get myself a service monitor...

      Scott
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