Think I have just blown the board. ft Orion Peizo



  • Hi Everyone,

    Bit of a backstory on the journey over the few weeks. I have a Tevo Little monster running a duet WiFI. I use a Piezo Orion for the Z probe and this was working great. The issue I had was that my bed just didn't work properly. Always having parts lift mid print. So, I build a new bed and install. All works very well and I think I finally have the printer working again.

    Cue Monday and the piezo probe starts failing. Starts activating during the dive. Played with a few settings but could only get it to either trigger in the dive or only trigger on a full head crash. I was playing with the screw that adjusts the sensitivity.
    I take the whole effector apart and put it all back together. Didn't find anything but i took the chance to shorten the cable the piezo uses.

    So just now in an attempt to get the probing working, I was trying to adjust the sensitivity screw and all of the stepper motors started jittering. Moving randomly.
    I killed the power. The piezo board has a bit of a smell but no magic smoke was released. All I can think is that either the power to the board got shorted or the power (3.3v I think) went into the Z probe In pin.
    I have no idea why or how this could have happened as i was doing the same thing multiple times over the last few days.
    Piezo board is wired to the Z probe 4 pin socket on the duet.

    Now when I power the duet it powers up BUT the screen does not connect and the WiFi does not connect. The fan is running and the fuse on the board is not blown.

    Any idea what could be broken and how I might be able to fix it??


  • administrators

    Are you able to connect to the Duet via USB?

    Is anything on the Duet getting hot? In particular, the main processor, WiFi module, SD card, or any other chips?

    Shorting +3.3V to Z probe In won't damage anything; but shorting +3.3V to a fan or heater terminal will.



  • I’m not sure how but given I took everything apart I guess it could have been a fan header that got shorted.
    If that did happen what would break?



  • Just comparing the lights to my other working duet board. The 3.3v light is NOT lighting up (The other 2 are) and the diag light is illuminated



  • Tried connecting over USB. The 5v light comes on but no comunication via YAT and the device is not shown on my computer.

    Also the micro Sd card holder got very hot. Not sure if that helps in anyway.



  • The Orion does not output a voltage, all it can do is pull down the SIG pin to GND.

    During testing, the only time any part of the Orion got hot was if the three pin cable was plugged in the wrong way 'round, is it possible this happened to you?

    DC42, is the 3v3 supply to the Z-probe connector on the Duet short circuit protected?

    Idris


  • administrators

    @moriquendi said in Think I have just blown the board. ft Orion Peizo:

    DC42, is the 3v3 supply to the Z-probe connector on the Duet short circuit protected?

    Yes. But it's not protected against shorts to heaters, fans, or other components powered from VIN or from 5V.


  • administrators

    @buzzby said in Think I have just blown the board. ft Orion Peizo:

    Also the micro Sd card holder got very hot. Not sure if that helps in anyway.

    That indicates that the SD card has blown, probably because of over-voltage on the 3.3V rail.



  • @moriquendi The plug was 100% the correct way as it was powered and i could see it triggering. (Blue light coming on and red going off)

    Still not sure what could have caused the short as i have no exposed wires. Have checked all cables for continuity and to see if they short anywhere but no luck.



  • @dc42 0_1562520534187_2019-07-07 18.19.23.png

    Shame on me. Never even thought to try booting the card without the card in. Card is not recognized in windows. And if i plug in USB i get the following lights and the card connects to the computer. Although i am not able to use YAT to connect to it as it says something else already has the connections. Might be something I am doing.

    I don't have a spare card so will order one. Can I just put in a blank card or do i need to apply an image?

    Do you think this means the card might still be good?



  • Meant to say does this mean the board might still be good.


  • administrators

    Try using the Erase jumper, to see whether you can get the Bossa port to appear on your PC. When the processor receives only mild over-voltage, sometimes it just corrupts the firmware in flash memory and you can re-program it.



  • The board will no longer connect over USB. Not sure if it is the board or my machine. Have switched USB ports but nothing.

    The WiFi module is quite hot while running. Is that normal or could that be broken as well.



  • @buzzby said in Think I have just blown the board. ft Orion Peizo:

    The WiFi module is quite hot while running.

    That's not usually a good sign.



  • @buzzby said in Think I have just blown the board. ft Orion Peizo:

    The WiFi module is quite hot while running. Is that normal or could that be broken as well.

    I got some experiences with those ESP8266 12E (the Duet's WiFi boards) as well. Not on the Duet but on my own fried PCB designs. I used an unstable power supply and fried them after a couple of months using a little overvoltage. The chance that your GND and 3.3V pin on the ESP8266 is shorted is very high.
    Could you check if the GND and 3.3V pin is shorted on your board? To check this you could simply use a multimeter and measure the resistance of the both golden pads named Gnd (15) and Vcc (8) in the ESP's pinout. It should not be close to 0...
    alt text

    If this is the case, the only solution would be to desolder the ESP and try again. I don't know if the ESP got a fuse, a 0 Ohm resistor bridge, or something? That could help a lot to 'deactivate' the ESP temporarily. If the short on the 3.3V rail is gone you could simply resolder an ESP8266 and flash a new ESP firmware. If you have the right equipment of course.

    Kind regards,
    Patrick



  • @corezair said in Think I have just blown the board. ft Orion Peizo:

    ESP8266 12E

    Thanks, Checking the pins the thing is shorted. I get continuity alarm across the 3.3 and ground.

    Could i try and swap out with a replacement one. They look pretty cheap to buy and I am ok at soldering. Should it work "as is" or would i somehow have to program the wifi thing before adding it back to the duet. Might be a fruitless task as something else on the 3.3 rail might have gone but could be good solder practice.



  • @buzzby said in Think I have just blown the board. ft Orion Peizo:

    Checking the pins the thing is shorted.

    That's not certain. I guess the 3.3V rail is supplying more devices than just the ESP. That the ESP is shorted is just a guess and there could be more shorts. Unfortunately there is no way to check each possible defective device on it's own. The only way is to desolder those one after the other until all shorts are gone.

    @buzzby said in Think I have just blown the board. ft Orion Peizo:

    Could i try and swap out with a replacement one.

    Before you do anything, do you still have warranty? Is this a case for warranty? Don't think so, right?
    @dc42 and the other PCB scholars out there, is there a way to disconnect the ESP from the 3.3V rail temporarily? Like a 0 Ohm resistor or similar?

    The best way to desolder the ESP is to use a SMD rework station. Do you have experience in desoldering big chips?

    After you desoldered the ESP check if the short is gone, if so, congratulations. Someone here should give you the needed information about which firmware to flash onto the ESP.

    Kind regards



  • @corezair
    I don't have an SMD station. Just looking at the price of one, it is probably prohibitive to try and repair. Although I might try with a normal soldering iron.

    Not sure if anyone on here would be interested in trying to repair it.
    This board is over a year old so suspect no warranty.


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