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Display has gone black, weird voice button behaviour

rasmusbrasmusb
edited April 2014 in Troubleshooting
I just finished building my LXR. I tested the display according to the build instructions and it worked fine. A couple of days later I got hold of a suitable SD card and popped it in. I then powered up the LXR again only to find that the display has gone completely black. I can start the sequencer and play sounds though.

There also seems to be some weird things going on with some of the buttons, although it's difficult to be sure since I don't know exactly how they are supposed to work and I don't have the display for feedback. But I'm pretty sure there is a problem with the voice 2 button... if I power up the device, start the sequencer, input some notes and press the voice 2 button, all voice buttons light up for a second or so and the sound stops (not abruptly... more like a fade out while all the voice buttons are lit).

Any ideas?

Comments

  • julianjulian
    sounds like you have a short somewhere.
    the voice 2 button should only switch to another voice channel.
    same behaviour as the other voice buttons.

    check that it does not touch some of the adjacent pins.

    as for the display - have you checked all the display pins and the pins on the AVR?
    the display is more or less directly connected to the AVR.
    is the AVR sitting tight in its socket?
  • azonicazonic
    i've got a black display on voice 4 in fm mode only...
    i'm using a 2.4 volt led on this voice.

    none other failures yet.
    'sup?

    thanks for assistance.
  • TrialanderrorTrialanderror
    The black display for FM in voice 4 is normal. The page is not available in that voice. 

  • azonicazonic
    thanks, i thought it was my fault.

    cheers
  • rasmusbrasmusb
    I checked for shorts with a magnifying glass but didn't find any. I fixed a couple of solder joints that looked less than perfect though.

    I tried to power up the unit 50 times or so and I am now even more confused.

    The problem with voice button 2 lighting up all voice buttons momentarily only occurs sometimes now (around 50% of the time). This time around I also noticed that the sequencer starts playing when this happens (the play button lights up and everything) and that voice button 2 works OK after the initial "glitch"... second time I press it, it works OK. I am also pretty sure the same thing happened with voice button 3 once, but I have not been able to replicate that.

    The display sometimes stays black, sometimes it lights up but is garbled, and sometimes it works OK.

    I can't really say if the two problems are related. The 5-6 times the display was OK the voice buttons were OK too, but that could easily be a coincidence.

    I have absolutely no idea how to troubleshoot this... please help.
  • rasmusbrasmusb
    edited May 2014
    OK, I thought I found a pattern in this but I guess not. I just powered up the unit again and when I pressed voice button 2 this time, the sequencer started running but the start button did *not* light up. Voice button 7 did, though. I can't stop the sequencer and when I press voice button 2, it starts blinking. When I press it again it stops blinking. The other voice buttons are dead and the display is black.

    This did not happen before...
  • nightworxxnightworxx
    edited May 2014
    Have you checked if all ICs are sitting tight in their sockets ? Your problem sounds like a wobbly contact, maybe related to mechanical stress somewhere.
  • rasmusbrasmusb
    edited May 2014
    OK, problem solved. I didn't realize that I had to press down *that* hard on the AVR.

    Thanks for the help, I am now the happy owner of one fully functional LXR :-)
  • nightworxxnightworxx
    You're welcome ! Not that this ever hapenned to other people here...*cough*
  • julianjulian
    hehehe
    maybe I should add a side view picture of a fully inserted AVR to the manual?
  • julianjulian
    congrats on finding the fault
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