Board not turning on -> polarity protection diode failed

sonalisonali ga tech
edited April 2017 in Cyton
I have the 8-bit Arduino compatible board.

When I turn the switch to PC or BLE there is no flashing blue LED. I have only used the battery pack that came with OpenBCI with 4 AA batteries. Multimeter shows output of each battery is 1.6 V, with the whole pack outputting little more than 6 V. The + and - terminals on the board also show a potential difference of a little more than 6 V, so I know the board is receiving power. Dongle is set to gp106 and has blue LED lit up, but board cannot communicate with it. Have tried resetting, but no response. I'm really confused.
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Comments

  • biomurphbiomurph Brooklyn, NY
    HI Sonali,

    use your multimeter to measure between the DVDD and GND pins. You should see 3.3V
    also, measure between the GND and AVDD|AVSS. You should see +2.5V and -2.5V respectively.

    These measurements are readable when switched to PC or BLE side of switch.
  • sonalisonali ga tech
    Hi, thanks for the quick reply!

    Between the DVDD and GND I am getting only about 1.2 V. GND/AVSS is almost nothing (.01 V) and GND/AVDD is 0.16 V.

    Pretty sure we have isolated the problem to the diode, which seems blown. When it is bypassed I get the LED response. I'm bewildered about what could've happened to the diode since there is no way to plug in the battery pack backwards and the batteries were always oriented correctly...

    I've ordered a replacement smd diode - hopefully soldering that in will fix the issue.

  • JCRTJCRT Majadahonda(Madrid)
    Same problem here.
    Could you tell me the specifications of the diode?

  • sonalisonali ga tech
    edited July 2015

    I have the 8-bit board - if you do too, the diode series is CDSU400B. Here are the details on Mouser, which is where I ordered my replacement. Soldering it in fixed the problem.

    If you have a different board, the diode specifications are given in the OpenBCI Docs in the Hardware section, somewhere within the PCB files.


  • JCRTJCRT Majadahonda(Madrid)
    Thank you, im using the 8-bit board too.
  • Hi all,
    follow up of my previous post: my 8 bit board looks dead, the LED stays off when I turn the swith on, no sign of any activity. Impossible to communicate with the board and upload the new firmware via Arduino IDE.
    Any suggestion ?
    Best.
  • biomurphbiomurph Brooklyn, NY
    @juldau
    Please tell us, what is your power supply? When you power the board on, or press the RST button, does the blue LED blink three times?
    Also, you say you are unable to upload firmware via Arduino IDE, can you be more specific? At what point does the failure happen?
  • Thanks for your answer. 
    Power Supply: I use as power supply the 500mAh Adafruit battery pack coupled with the Adafruit PowerBoost (I have the 8 bit board expecting 5V as input) as suggested by wjcroft at the bottom of this page (https://sites.google.com/site/biofeedbackpages/velcro-sensors).
    After noticing the problem, I immediately tried powering it up with the original 4 battery pack (new batteries) but no success.
    LEDs: no blue LED blinking at all when powering it on, or pressing the rst button (or any other action, the LED does not light up anymore).
    Firmware update: despite the fact that the LED did not blink at startup, I tried uploading the firmware using Arduino IDE, but I soon as I hit upload, it stops after compilation saying that no board is detected.
    To sum up the present situation, the board has no reaction of any sort and does not connect to anything (Processing, Arduino IDE, OpenVibe).
  • biomurphbiomurph Brooklyn, NY
    @juldau,
    It sounds like the board is not getting power. This could be a component level problem. If you have a multimeter, I suggest trying a test:

    Find D9 (on the bottom of the board) This diode is the protection diode for the circuit (prevents reverse bias on the power input) it connects from the GND of the board to the - input of the battery. Set the multimeter to 'diode test' and measure the Vf of the diode. It should be about 1/2 volt or so. If you don't have a diode test setting, then power the board, and try to measure the voltage of the board. If you don't see 5V or 3V on the power pins, this diode may be blown.
  • @biomorph,
    OK I used the "diode test" setting of my multimeter and measure D9 voltage (both directions as I don't know which is ground): I found 0.
    To make sure my measuring is correct, I tested D1 on the other side of the board and found 0.559V. So looks like the D9 diode is blown... Thanks for your suggestion of test, sounds like it's definitely part of the power problem. Shoud I try to change D9 (any reference) ?
  • biomurphbiomurph Brooklyn, NY
    edited December 2015
    For D9 we are using a Comchip Diode part number 

    CDBU0130L

    It is an 0603 package, so not too impossible to hand re-work.
    Here's a link to the mouser product page
  • OK thanks for the ref, I'll look into it. Looks like you need some skills to solder that by hand but I'll try and let you know.
  • Hi,

    I have an 8-bit board which stopped working recently.I don't get any data streaming in, but an empty .txt file gets created.
    I tried measuring the voltages between the pins as mentioned above. I'm getting 3.3V between GND-DVDD and 2.5V between GND-AVDD but 0.5V between GND-AVSS pins. 

    Can someone please help me figure out the issue?

    Thank you 

  • biomurphbiomurph Brooklyn, NY

    You should be getting -2.5V between AGND and AVSS, +2.5V between AGND and AVDD, 3.3V between AGND and DVDD.
    Double check and let us know. If you are not getting AVSS, then that would be a problem. I don't think you should expect to get an empty txt file, however...
  • Hi,

    I checked the voltages again. I'm not getting -2.5V between AGND and AVSS
    I'm getting 0.5V between AGND and AVSS,
     +2.5 between AGND and AVDD 
    3.3V between AGND and DVDD

      
  • biomurphbiomurph Brooklyn, NY
    @indra
    Yipes! that's not right. 
    The negative voltage is created from the 5V regulated power on the 8bit board. The 5V first gets inverted by U3, which outputs -5V that goes to the IC labeled VR1. That chip regulates the -5V to -2.5V

    Since the rest of you power supply looks stable, it may be a fault with these chips. Please use a magnifier or loop do a visual inspection of U3 and VR1 to see if any of the pins are damaged, or if there is some issue on the surrounding board. 
  • @biomurph

    I think the problem might be with U3. The pins seem fine, but the chip gets heated up when the board is powered on.

  • @biomurph,
    I had D9 replaced and it worked, my OpenBCI is back to life! Thanks for the tip.
  • biomurphbiomurph Brooklyn, NY
    Is there anything that looks like a short on the board?
    Can you do a continuity test with a multimeter between AVSS and AGND?
  • I did a continuity test between AVSS and AGND. There is no continuity between AVSS and AGND.
  • biomurphbiomurph Brooklyn, NY
    Hi Indra,

    Please contact me joel-at-openbci-dot-com and we will try to resolve this issue.

  • My openbci board keeps not turning on. I've changed the D9 diode and measured voltage between GND, DVDD, AVDD and AVDD. I got 0 V between GND and DVDD, 0.001 between GND and DVDD, 0.002 V between GND and AVDD, 0 V between GND and AVSS. I did continuity test between AVSS and AGND. There is continuity between AVSS and AGND. The D9 also fine, I've checked the continuity and it's fine.
    What should I do to fix those problems?
  • biomurphbiomurph Brooklyn, NY
    @syifalianti
    Please let us know a few things.
    Do you have an 8bit or 32bit board?
    How long have you had it, and when did it stop working?

    It does sound like the board is not getting power. Can you confirm that D9 is in correct orientation? Verify that your power supply is good, and chase down the V-in. Where do you stop seeing it?
  • syifaliantisyifalianti Indonesia
    edited April 2016
    I have 32 bit board.
    I have it since January 2016, so it has been 3 months. It stop working 2 weeks ago.
    D9 diode is in correct orientation, I've checked it and it shows the right value.
    Power supply is in good condition, I'm getting 5.66V at V-in
  • biomurphbiomurph Brooklyn, NY
    @syifalianti
    Please email me joel-at-openbci-dot-com and we will see if this is an issue that we can correct or replace.
  • I have a 32 bit board.
    I have it since 2015 and it has been working fine. I was uploading the firmware to change sampling rate and during the process the blue LED on the board turned off. Now it is not working, neither it is communicating with the dongle to connect to the PC.
    V-in is 5.90V.
    We are getting -2.5V between AGND and AVSS, +2.5V between AGND and AVDD, 3.3V between AGND and DVDD
  • biomurphbiomurph Brooklyn, NY
    @asd786
    can you reprogram it with the stock firmware to verity that you have not caused the problem with your software changes?
  • I am able to put it in the bootloader mode but when I try to reprogram it using Arduino IDE the sketch compiles well but while uploading it gives an error "Program flash failed".
  • biomurphbiomurph Brooklyn, NY
    This is a known issue that we are having. Currently, we are working on an upgrade of the radio firmware, and in the process, we have made some discoveries that might help in the uploading process.

    For example, we flash the firmware on all boards over air here in the lab, and have very few failures.
    One thing that looks like it may be an issue is when you are working with an older, or slower computer. This could be an issue.
    Also, try rebooting the computer, and ONLY run the Arduino IDE. No other programs running. Also, if you have any other programs running, do not move away from the Arduino IDE window until the upload process ends.
  • @biomurph,@juldau
    I went successfully through the same diode replacement process.
    Definitely the way to go. Just want to add that the way I burned the
    diode was by plugging a 3.5V / 400mAh lipoly battery on the openbci
    board version 3-8, which actually requires 6V -12V. So it looks like low
    tension matters.
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