High Pitch squeel from Melzi after flashing firmware

After getting the bootloader on my Maker Select V2 (Wanhao) Melzi board, I was able to compile and flash the Repetier firmware to my board (0.91, 0.92, and 1.0.x) - "stepperWait" issue notwithstanding.

After avrdude reads back/verifies the load was successful, I get the Repetier logo on the LCD, but I also get a high pitched sound from the board (whether power from USB or from power supply).

The printer/LCD appear to be functioning (can navigate menus, "Home All", etc.), but the noise is VERY annoying, and I'm afraid it is a sign of something that could fry one or more components on the board...

Oh, and while flashing the firmware to the board, the sound goes away (only to return when the board reboots [after the flash is complete]).

Any thoughts/suggestions?


  • If you have main power off does the sound still happen? Don't have a melzi board but normally boards are silent - sounds come from motors loosing steps or getting wrong current or fans with not enough power to run  or piezo on display controller - something like that. With only 5V from usb these should not get any power so you can test if it comes from that. If it does you can unplug them and connect part by part until you know what it is.

    Sometimes components also make sound when switching at high freqency but firmware uses 16Hz basic frequency for heaters/fans nothing you can hear.
  • If it is a loud squeel, i would plump for the piezo sounder on the display being activated.

  • edited November 2018
    Thanks all!

    Martin, you were spot on...

    After trying (in vain) to find a Display Controller selection that would work (and/or SOME documentation on what LCD is used in the Maker Select/Wanhao), I stumbled upon a write-up on making the Wanhao LCD work on the RAMPS board (showing the pin-outs).

    I then looked into pins.h (in the MOTHERBOARD == 63 [the Melzi board]), and found that the "LED_PIN" is set to 27, which (according to the write up pin assignments) is the BEEPER on the LCD board.

    I changed the LED_PID to -1, and Voila, no more noise!

    Yes, it would be nice to know what pin on the Melzi board corresponds to the LED, but I'd rather have NO LED and NO High Pitched squeal (especially considering with LED_PIN set to the BEEPER, I probably am NOT getting the expected LED indicator anyway).

    Again, thanks for your help!

    Oh, I used the "RepRapDiscount Full Graphic Smart Controller 128x64, RAMPS, Rumba, Megatronics 2 & RAMBO" selection.

    p.s.  Might be nice to the pins.h updated, don't you think?

  • At least in dev version it was already -1 :-) So in 1.0.4 it will be as well then.
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