No sound and voltage question
  • Hi,

    Newly assembled kit for Eurorack. Not getting sound from main out, but am getting sound from the audio out on the front panel. All power points checkout at proper voltages. However, voltages read 0.0 at the audio out points on the PCB. Used correct pot for volume control.

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    1978 x 1090 - 727K
  • > However, voltages read 0.0 at the audio out points on the PCB

    With the meter in DC or in AC mode?

  • DC mode.

  • Then it’s normal to read 0V, the signal is not to be supposed to have a DC offset. Best way to probe audio signals are:

    • Oscilloscope.
    • Connecting to a mixer/audio interface/amp and listening to what’s there.
    • Multimeter in AC mode (won’t tell you much besides the order of magnitude of the signal amplitude).

  • I’ve connected it to my audio interface but no dice. I’ll try the oscilloscope and post the results.

  • My bad, what settings should I use for the scope?

  • 200mV or 500mV per div vertical ; 1ms per div horizontal.

  • Started troubleshooting this morning, but on power up no lights. All power checks out, signal path checks out, however MCU shows trouble.
    Position 10 – 3.94v but no steps on scope
    Pos 11 – no steps
    Pos 12, 13, 14 – no signal
    Pos 15 – square output wave detected
    Pos 16 – no carrier detected at 39kHz

    Chip seated correctly and orientated. Bad MCU? Was working yesterday as I was playing around with the drums.

  • If you want you can send me back the chip and I’ll have a look…

  • Will do. What is your address again?