Troubleshooting • Re: Raspberry pi 400 damaged by over voltage

How did you get >5V on USB-C? Rogue PSU? Or just a non-compliant power supply system? What voltage did it get? And what current was available?

I think the Pi400 has a TVS diode for overvoltage protection. If so, it has probably sacrificed itself to save your Pi. Proceed as follows:

1. Locate the TVS diode on the PCB (sorry, can't help with that on a Pi400).
2. Remove it.
3. Test the Pi with a known good, preferably RPi. 5V 3A (or PD) PSU -- such as the ones made for Pi4 or Pi5.
4. If it works:
   • shut down,
   • disconnect,
   • obtain a new TVS,
   • install (observe polarity),
   • resume normal Pi operation.
5. If it doesn't work, there is probably damage to multiple chips. Repair is unlikely is succeed.

Do not be tempted to run long-term without a TVS diode. Any future PSU accidents would certainly destroy the Pi.

Statistics: Posted by davidcoton — Sat Dec 07, 2024 5:35 pm

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