Photon: SOS+1 / Extremly hot / short

the story goes like that: I powered a 128x64 OLED Display by the Photon’s 3v3 pin, together with a I2C temperature sensor. Everything was powered with a (now presumably) faulty wall power supply that should have given the board 5V over the VIN pin.
The system worked for about 20 minutes, that’s when I noticed that the display doesn’t show anything new and the LED wasn’t breathing blue anymore, just a static blue at this time (like frozen). I immediately disconnected it from power and noticed that the whole board was extremly hot.

I repowered it with another power supply connected to the micro USB. The device starts with SOS+1, when I try starting it in safe mode it just restarts to SOS+1. However, DFU mode works.
I then conncted it to my laptop doing “particle update”/“particle flash --usb tinker” which tells me that both operations where “successful”, but the photon still restarts only in SOS+1. I then notice, that my device still gets extremy hot: Measured between 3V3 and GND there seems to be a short, but there is no short between VIN and GND (the pins I first used to power the device) and the both outer micro USB pads (what should be +5V and GND).

Is there anything I can do or did I fry it for good?

Thanks for your help

If you have a 3v3 supply, you can fit it directly to the Photon and see if it works.

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Let us know if Kenneth’s fix helps @shnytzl.

I don’t have a 3v3 power supply, I tried powering it with an Arduino through its 3v3, but that didn’t work, voltage breaks down to around 2v.

Sounds like the Photon is damaged.

You might want to remove all the circuitry and only power up the Photon just to be sure.

Removing everything else was the first thing I did. I ordered a replacement RT8008 DC-DC converter, how are my chances this will fix it?

The Uno supply can only provide 50ma which may explain why you are seeing a 2v level. You really need to test the Photon with a 300-500ma supply. If the STM32 is blown, a new RT8008 won’t help.

If you haven’t got a reliable 3.3V source another Photon can give you enough current off the 3v3 pin for testing.

Thanks for that tip! Unfortunately the photon in question starts in SOS+1, so I guess it is dead… Should I try the new RT8008 or is that futile?

SOS+1 does indicate that at least some life is left in it :wink:
You could unsolder the supposedly frazzled regulator and try 3v3 power and DFU mode

particle update
particle flash --usb tinker

You could also try to reflash the bootloader - binaries should be available on GitHub.

Unsoldered and tried to update and flash the tinker script, both operations were “successful”, but the Photon itself keeps restarting in SOS+1. Didn’t try the bootloader binaries yet.