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Added Trigger Extension, cannot enter steps anymore

newnoisenewnoise
edited May 2014 in Troubleshooting
Hi,

today I finally found the time to add the Trigger I/O Board to my LXR. I bought the LXR used a couple of weeks ago. As I found out today it seems to be the old version of the PCB, because there was no place for the ribbon cable connector. So I followed the instruction on how solder the ribbon cable directly to the mainboard. Pretty annoying, needed 4 hands for that (thanks to my patient girlfriend!), but got it all together.
So, first start, just weird chinese signs on the screen. Getting scared. Restart, everything seems fine. Puuh. Then I wanted to setup a simple beat to test the I/O Extension, as the instruction advices, AND I cannot enter steps anymore. I can do everything, select all voices, load patterns, go the menu etc. pp. but I cannot enter steps, for not one of the voices.
I unplugged the extension, same fault, replugged the extension, first boot: chinese signs. Second boot ok, but still cannot enter steps.

Rechecked the wiring, everything seems fine.

What now?

Thanks
noise

Comments

  • julianjulian
    could you post a picture of your soldering job on the mainboard?
    is it working if you unplug the trigger IO board?
  • newnoisenewnoise
    Hi,

    no unplugging does not help.
    Pictures comes later when I'm at home.

    Thanks
  • julianjulian
    not being able to set steps and starting/stopping the sequencer are sings that the mainboard is not running propperly. so either you plugged it in wrong (I already managed to insert it with a 1 pin offset and wondered why it was not working) or you made a short somewhere while soldering the cables.

    try to make a close up of the solder job in good resolution.
  • newnoisenewnoise
    Hi julian,

    I'm very sure that I soldered all the pins correctly. But here is a picture, I hope it is good enough:
    https://dl.dropboxusercontent.com/u/7542095/P5062524.png

    What I also cannot do ist a firmware upgrade. Tried to do it to reset all settings. Did not work, or at least I canceld it after 30minutes. I was trying to "upgrade" from 0.32 to 0.32, so maybe that ust does not work?

    Everything else works fine, I have the extra menu for the trigger extension, so the board seems to recognize the extension and all other functions are available.

    Thanks,
  • julianjulian
    edited May 2014
    look at the top right corner of the cortex chip (STM32)
    it seems you droped some solder on some of the pins. (next to C12)

    this probably prevents the CPU from running at all. hence all mainbaord functions (updates, setting steps, running the sequencer) are not working.

    The UI is handled completely by the AVR alone and would even work without a mainboard installed.
  • julianjulian
    do you have a desoldering braid or a solder sucker?
  • newnoisenewnoise
    Oh, you're right. Dammit. Hope this didnt fry the Mainboard?
    I got this one here: http://www.elektronik-24.de/images/articles/882_2a780f549f7f365724d01b0c514cec40_5.jpg

    Thanks
  • julianjulian
    very unlikely you fried it.

    the pins connected by the solder blob are the TX and RX pins used to communicate with the frontpanel.
    that explains why the mainboard is not responding to button presses.

    you just have to be carefull while trying to remove the blob not to fuse even more pins toghether.
    With desoldering braid it is very easy. I never tried it with a solder sucker, but it should be possible as well.
    if you are lucky maybe you can even just scrape the blob off with a needle if it is not completely melted to the pins. sometimes something like this is just attached very lightly. depends on the temperature it had while landing on the pins (don't use excessive force here, or you might bend the pins or tear off a pad)
  • newnoisenewnoise
    hi julian,

    I was able to remove it with just a needle, and I found another spot on the chip which had a solder blob on it (I marked both in the new picture: https://dl.dropboxusercontent.com/u/7542095/lxr.png) Guess you should NOT do those soldering jobs on a late sunday night ...
    I think I removed the blobs completely, but I still cannot enter steps. Maybe the second blob was at a critical point?

    I really hope I didnt do any irreversible harm to the mainboard.

    thanks a lot for your support!
    Tom
  • julianjulian
    those 2 pins are used for the trigger IO clock in and reset in.
    so the LXR should work 8just those 2 inputs not)

    is the synth recognized by the computer if you plug the USB cable in?
  • newnoisenewnoise
    Will check that tonite when I'm home from work again.
  • julianjulian
    the thing is - if it is recognized as usb device we know the STM chip is running.
    this has nothing to do with the frontpanel at all besides that the USB plug is located there.

    If it is recognized by the computer, we know that the problem lies in the communication with the frontpanel.

    maybe you can take another picture of the board with the blob removed. So we can zoom in and see if it was removed completely.
  • newnoisenewnoise
    Yes. I will do that tonite, or maybe tomorrow morning, because I'm not sure when I will be home!
    I really appreciate your support!
  • julianjulian
    you're welcome :)
  • newnoisenewnoise
    The computer does not recognize the LXR. Which I suppose is bad ... :(
    I rechecked both spots, they really seem fine to me now. I tried to make another picture, but I dont think its good enough.
    https://dl.dropboxusercontent.com/u/7542095/P5062534.png
    And now? New Mainboard?


  • julianjulian
    bottom left, once again next to C12 looks suspicious.
    this time the 1st two pins
  • newnoisenewnoise
    I rechecked every pin on the chip for 32 times (estimated :)) and really cannot find any of these connected anymore.
    Can I check something else?
    This is so unnecessary, aah.
  • julianjulian
    could you measure for continuity on the mainboard between a 3,3V pin and the 2 sides of C12 (with the mainboard disconnected from the front). just to be sure. I still think this looks suspicious
    image

    also verify that you have 3.3V on the 3.3V pin while the mainboard is connected an the LXR is powered on.
  • newnoisenewnoise
    Ok, I will do that. Not before friday though, no time before, I will post here when I checked it!

  • newnoisenewnoise
    edited May 2014
    Okay, so for the continuity:
    PIN 1 and PIN 2 have continuity to the bottom side (in the picture above) of C12.
    From PIN 3 upwards they don't.

    Measuring the voltage between PIN 1 and bottom Side of C12 is 1.6V, between PIN 2 and C12 0V ...

    I'm afraid of the worst.
  • newnoisenewnoise
    should I order a new mainboard?
  • julianjulian
    Okay, so for the continuity:
    PIN 1 and PIN 2 have continuity to the bottom side (in the picture above) of C12.
    From PIN 3 upwards they don't.
    this sounds to me as there is still a short between pin 1 and 2 (the one with the arrow)
    this is how it should be connected
    image

    you are located in germany?
    I you don't think you can remove the solder by yourself you could send me the mainboard to fix.
    Should be possible to send as a großbrief (1,45) or maxibrief (2,40)
    so about 5€ in the worst case ;)
  • newnoisenewnoise
    Hi Julian,

    okay that sounds better than I expected. I will have another look at it tonite and if I don't succeed I will gladly send the mainboard to you, thanks a lot for the offer!

    I will contact you via the contact form then, so you can give me your address.

    Thanks so much!
    Tom
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