analog discovery 2 repair

[kernalex]

Hi, just happens,

small explosion and small boxed element under USB connector is gone. The second (looks pretty same) is still here, but I cannot map these elements to schematic... Anybody here who knows?

 

BTW happens as I tryed to connect ground of scope to USB connector shield? Used to do that quit often without any damage. The only difference that this time I connected both, via my monitor (these USB were the nearest). Monitor survived but project and AD2 both are dead... Some ideas?

 

/BR

Alex

[kernalex]

correction: USB on monitor can still deliver 5v but device attached to it is not recognizable...

[JColvin]

Hi @kernalex,

To make sure I understand what happened correctly (as so the engineer much more familiar with the Analog Discovery 2 can see the details), you put the negative input of the oscilloscope (either 1- or 2-, the orange wire with a white stripe or blue wire with a white stripe if using the 2x15 flywire set) to the USB shield and that was when the explosion (literal?) occurred? Were you using the BNC Adapter for the Analog Discovery at this time, or just the Analog Discovery 2?

Thank you,
JColvin

[attila]

Hi @kernalex

Your circuit's ground probably was at different potential than the computer/monitor/AD2.
This could happen because of using grounded supply rail as ground for circuit or problem with the wall socket earth, like accidentally it is wired to a phase.
Such causes high power surge/short circuit. The ferrites in the AD2 under the USB connector act as a fuse but likely other ICs are also damaged.
Luckily you are unharmed and the computer/monitor survived it.

See the following post:

 

[kernalex]

17 hours ago, JColvin said:

Hi @kernalex,

To make sure I understand what happened correctly (as so the engineer much more familiar with the Analog Discovery 2 can see the details), you put the negative input of the oscilloscope (either 1- or 2-, the orange wire with a white stripe or blue wire with a white stripe if using the 2x15 flywire set) to the USB shield and that was when the explosion (literal?) occurred? Were you using the BNC Adapter for the Analog Discovery at this time, or just the Analog Discovery 2?

Thank you,
JColvin

Hi @JColvin,

I've used BNC Adapter. The AD2 seems to be dead. Neither via USB nor +5V adapter none of ADM1177 generates signal to open MOSFET.

I think more and more that my carelessness is the source of issue. On the second probe ground crocodile clamp I found the trace of high current flow. And the list of my damaged items grows. The switched power supply of my project is also died. Probably during my attempt to connect first crocodile clamp to USB shield, the second touched the high voltage part of power supply (was not covered). The high current loop went through BNC/AD2 ground plane to USB HUB killing all on the way. Additionally the Arduino NANO, USB shield of which I tried to use is also damaged. I can talk to it but ROM isn't writable anymore.

So there is no much hope for me. I will really miss AD2. Is there any way to order only main piece of AD2 as spare part?

 

BR

Alex

 

[kernalex]

3 hours ago, attila said:

Hi @kernalex

Your circuit's ground probably was at different potential than the computer/monitor/AD2.
This could happen because of using grounded supply rail as ground for circuit or problem with the wall socket earth, like accidentally it is wired to a phase.
Such causes high power surge/short circuit. The ferrites in the AD2 under the USB connector act as a fuse but likely other ICs are also damaged.
Luckily you are unharmed and the computer/monitor survived it.

See the following post:

 

Hi,

 

Thank you for advice.

It seems that it's me who created shortcut between high voltage part of project and AD2's ground plane. And I'm really in luck to have both connected to the same USB hub of my monitor which I'm not really use so often. Otherwise I would be in need not only for new AD2 but also for new PC. Likewise my monitor survived without any problems (Only integrated USB hub died, but can still deliver 5V. I can use for a lamp ;-))

 

BR

Alkex

[Vandy12]

I hope this doesn't happen to me. Lesson learned. As a diver, I used to read all the things that killed people underwater. Now I read about all the people who get killed with electricity. It is dangerous!! Be careful!! I bought a pretty nice kit from Elenco. It is a well known adjustable power supply. Do I need one? No. Did I want to build one for the fun of it? Yes. I am OK at soldering not great. Pretty new. I took my sweet time and soldered it all together and everything looked to be in order. The guys with experience said, "I did it in one afternoon." Took me three days. Again, I took my time. I plugged it in and nothing happened. Fuse I forgot. Put the fuse it and it worked!! It lit up!! I was just getting ready to check the output and got up for a stretch and walked out of the lab. I was in at my kitchen table and heard this, "KaBoom." Oh that did not sound good. I am so glad I didn't have my face down in the power supply looking at it. A capacitor blew. I never did find out why. So of course I did what any science guy would do, I watched capacitors blow up in slow motion on Youtube. I learned something. They are built to blow up slowly. They have an X mark on the top to relieve pressure in case they overheat and then then just fizzle. Well I hate to tell you this but this capacitor did NOT fizzle. It blew up. I found the external casing and it was still totally intact. Still had the FAILED X on top and somehow, some way the capacitor failed to do what is was suppose to do and did not blow up the right way. Instead of a fizzle it was a freaking bomb. It was not like the little explosions I saw on the Youtube videos it was LOUD. I sent the unit back to Elenco, got refund, no questions asked. What caused this? I have no clue. I just can't even believe I would have put the capacitor in backwards. It must have been something else. Never did figure out what caused it. Some newbie bad wiring I guess. In conclusion to this huge tome of a response, I would like to say this. If you build a project using AC current, before you plug it in after the build, put on goggles and ear protection before you do so. Maybe even a bomb protection suit. Or plug it in outdoors and get away from it and watch it. Be very careful. Again, I'm glad my face was not down close to this capacitor when it blew.