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tabularasa

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Posts posted by tabularasa

  1. Name            PCB BLM   PCB miniCore   Case   Shift button   M2 hardware   4xLED
     
    latigid on      1         1              1      1              1             1
    Rowan           1         1              1      1              1             1
    Phatline        2         2              1      2?             1             1
    TK              1         1              1      1              1             1
    Altitude        1         1              1      1              1             1
    rwo             1         1              1      1              1             1
    jojjelito       1         1              1      1              1             1
    tashikoma       1         1              -      1              -             1  
    workspace       1         1              1      1              1             1
    flyweight       1         1              1      1              1             1
    Grizz           1         1              1      1              1             1
    blingy          1         1              -      1              -             1
    ganchan         1         1              1      1              ?             1
    Macotronic      1         1              -      -              -             - 
    sbm             1         1              1      ?              ?             1
    Jack            1         1              1      ?              ?             1
    tabularasa      1         1              1      ?              ?             1
     
    Total          18         18             14     14             10            16

     

    I'm in with one of each.

  2. Thanks a lot for the hints.

     

    Today I resoldered the 2 74HC595 today but there is no difference. The orientation of the resistor networks is correct andI think they are in line to read encoders and buttons which is working fine.

     

    There is a resistance of 43 kOhm between the QA-QH outputs and the ground connector of the 595 shiftregister, is this normal or shall I look look for shorts?

     

    I can also measure a resistance between the outputs of the shifregister 1 and 2 (Out vs DOUT) but these are serveral MOhm, so I don't think this is the root cause of the problem.

    .

    Is there a good methology to track down the root cause?

  3. Hello,

     

    I soldered the LEDs on a SEQ V4 panel and some of them keep glowing dim when they should be off and one is always glowing very bright. I checked for shorts but couldn't find anything. Then I changed the 74HC595s but I have still the same effect. Debugging is really difficult since I can always measure a voltage between the pins of the LEDs.

     

    The config file is is a copy from here: http://svnmios.midibox.org/filedetails.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fsequencers%2Fmidibox_seq_v4%2Fhwcfg%2Fwilba%2FMBSEQ_HW.V4

     

    According to Wilba's schematic all of the missbehaving LEDs share a connection to Out14 but I could no find a shortcut between this line and other connections on the board.

    http://midibox.org/forums/index.php?app=core&module=attach&section=attach&attach_id=8731

     

    The Track and Track Group LEDs are less bright if I switch on the step LEDs.

     

    The power source I'm using is a Meanwell RTP-60B with 100kHz switching frequency connected to J2 and on Core STM32. Might there probably an issue with the multiplexing frequency or do you have an idea what could be the root cause? I'm quiet lost and don't know how I can effectively troubleshoot this issue.

     

    Seq_v4_panel_LED_issue.png

     

    Martin

     

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