Troubleshooting boot/start: top 4 LEDs only light (bottom 4 blink quickly)

Finally got time to finish the kit, with the jacks board.

Power-up, I get the top 4 LEDs to light, and the power LED, and that's it. I suspect it's a CV/Clock thing (perhaps).

I've checked the components and solder traces for cold/shorted, and the wires from the main board to jack board seem correct. 

Anything obvious jump out to check? It won't boot into debug mode (doesn't appear to be booting at all, actually).



  • FYI all the audio stuff works, signal passes through to the out and is clean, it just doesn't appear to boot up any
    of the digital stuff.

  • Hi Mike --
    Just to be clear, the topmost 4 LEDs all come on and stay on, is that correct?
    Do any lights fade up or down, or do they just come on as soon as power is applied?

    Does anything get hot?

    Also -- if you suspect a clock problem, one thing to check is that the caps associated with the crystal (C1 and C2) are the correct values.  They should be 20pf caps.  Those look very similar to the  0.1uF caps used everywhere else, but the MCU's clock won't work if they are the wrong value.  The bottom row of text should be 22J and not 104.

    Let me know, and good luck,

  • Hi Todd,
    Thanks much for your help!

    Yes, the top 4 LEDs light and stay lit. Nothing else fades up or down, and I don't notice anything abnormally hot. The
    only thing warm-ish is the regulator. The bottom 4 LEDs blink very quickly, just looks to me like power being applied 
    makes them light very briefly (so I know they aren't dead/fried).

    The caps next to the crystal are correct (22J/20pf).

    I have more time this evening to dig in and test, and will check solder and components again. If I still am stumped
    I will let you know.

    Thanks again.
  • Thanks for the tip to look at the two 20pf caps. I'm not sure if they weren't soldered well,
    or if it was the crystal itself, but resoldering those fixed it.


  • Glad you got it working!  Have fun.

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