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One of my many Raspberry Pi 4's in one of my clusters recently broke down. After some troubleshooting, I was surprised to find out, that the power circuit on the board was actually toast. I have no idea how this happened but now I can no longer power the board via the USB-C plug.

From the schematics, I could see that these pins lead directly to the 5V0 and GND rails "behind" the VRMs and caps in the power circuit of the board.

Since I don't have another stabilized power supply I can spare and I need the Pi up and running asap, I'm asking whether I can power the Pi via the GPIO +5V and GND using the official USB-C adapter (by just soldering a USB-C jack onto them) or if that would lead to damage or even catastrophic failure over time.

Soldering extra caps onto the "auxillary" USB-C jack is no problem if necessary. I just wanted to ask some people with experience and maybe even better ideas, before I try something untested and fry an otherwise good Pi 4.

Edit for clarification: With "power circuit" I mean the MXL7704 PMIC and the caps right behind the USB-C port. Although the PMIC receives input voltage, its outputs are all on 0V and it gets up to 75 degC hot. I could not identify any shorts on the board.

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  • "the power-circuit on the board is actually toast" what is this mysterious power-circuit and how did you decide it "is actually toast"
    – Milliways
    Feb 10, 2023 at 6:22
  • @Milliways With "power circuit" I mean the MXL7704 PMIC and the caps right behind the USB-C port. I checked the USB-C plug first (5.05V), then the 5V and GND rails (0V) and then the outputs of the PMIC and fount that they all are at 0V although power is reaching its inputs. Plus, it gets HOTTT. 75degC on the FLIR... which, I can assume, is far out of spec. That's why I said it's "toast".
    – Caeleste
    Feb 10, 2023 at 12:14
  • @Milliways I can remove the PMIC without any issue and replace it but this will take a while (shipping and stuff)
    – Caeleste
    Feb 10, 2023 at 12:54

3 Answers 3

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"I'm asking whether I can power the Pi via the GPIO +5V and GND"

If you know the PMIC is dead this is a meaningless question.
The PMIC inputs 5V and generates all the voltages the Pi ACTUALLY uses.

It doesn't make any difference where you put 5V - it WON'T WORK.

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Just a curious thinkerer here (with some experience in electronics): if the circuit is "toast" means some componentes are either shorted or open (and maybe some traces are open as well), so you should first remove the bad components from the circuit board.

It is indeed possible to power the Pi from GPIO, here Safe power supply through GPIO pins

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If the IC is toasted, then there are two possible reason.

  1. The one @Clóvis Fritzen described.
  2. Your power supply spiked. Check your PSU(Which I think you already did)

If @Clóvis Fritzen is right then you have to open datasheet and check every pin with multi-meter if it is okay. If every responses are OK then you can change the chip(if available). But my suggestion is to throw it away.

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