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foostan / crkbd

Corne keyboard, a split keyboard with 3x6 column staggered keys and 3 thumb keys.
Creative Commons Attribution 4.0 International
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Killed the rPi by first time powering up with connected TRS cable? #243

Open MaxWinterstein opened 3 months ago

MaxWinterstein commented 3 months ago

I ordered 5 PCB pairs. 4 Work great, but 1 is missing any signs of life.

When I tested them, I accidentally powered one factory new PCB pair with a connected TRS cable. Is it possible to fry the chip when doing this? Like a brand new chip contains some firmware that has voltage where there shouldn't be any?

foostan commented 3 months ago

I don't know your situation, but a certain number of defective products can be included. Please contact the factory.

gpmontt commented 3 months ago

Maybe you need to secure the TRS cable. Some diodes can be helpfully here

foostan commented 3 months ago

v4.1 is TRS compatible

defekkt commented 3 months ago

had the same issue, might have been a voltage spike when connecting TVRS cable after connecting USB. turned out it killed the V-USB-> 5V Diode. might be worth checking for you too ;-)

foostan commented 3 months ago

Do not connect the TRRS/TRS after the USB cable has been connected. However, it would be a good idea to add a protection circuit to the TRRS/TRS connector as well. I will consider this. Thanks.

MaxWinterstein commented 3 months ago

@defekkt can you give me more information on that? Not sure where this diode is, and how to check it. Thx :)

defekkt commented 2 months ago
  1. grab a multimeter, put it in diode mode
  2. on a known-working/good board/diode measure the diode in both directions
  3. then check it on the faulty board, compare the values (should be different depending on the direction).

here is the diode, next to the usb-connector corne_vusb_diode