T-Beam Supreme only powers on with USB

[chaosaffe]

Hello,

I've recently recieved a T-Beam Supreme (M) that will not power up when on batter power.

I've used the pins to check voltage, and I have

• 4.19v on VBAT to GND
• 0v VBUS to GND
• 0v VSYS to GND

My electronics knowledge is quite limited, are there further troubleshooting steps I can take to identify the issue?

Thank you in advance for any suggestions and assistance

[teastain2]

@chaosaffe said in T-Beam Supreme only powers on with USB:

T-Beam Supreme (M)

Do you edit the firmware in Arduino IDE ?

[chaosaffe]

@teastain2

I have not edited the firmware, the device is running v2.2.11 of the Meshtastic firmware.

[teastain2]

@chaosaffe So, as I thought. hmm...Some LilyGO products need a special power on GPIO to be set, in order to get Battery Power. It stumps most people, including me, until someone figures it out!
Since you run the shipped-firmware, it can't be that.
It is very hard to even find a schematic for these, I'v been trying since yesterday.
I'll keep digging.
Please check here again for any updates.
I don't think '0v VSYS to GND' is correct and maybe the answer, IF either of us can find a schematic!
-Terry

P.S. OK, this might be it:
https://github.com/Xinyuan-LilyGO/LilyGo-LoRa-Series/blob/master/schematic/LilyGo_TBeam_S3_Core_V3.0.pdf
Here are some salient points.
The Power ON key to the APX power supply chip

And its hardware switch:

[teastain2]

@chaosaffe This just posted by another user:
https://community.lilygo.cc/topic/716/t-a7608-gsm-modem-does-not-work-in-battery-mode

[chaosaffe]

@teastain2 Thank you Terry for taking some time to investigate!

Unfortunately the schematics are a bit above my head. Are there some pins or components on the board that you're recommending I test?

I should note that the device does not seem to recognize and charge the battery when it is installed. I am suspecting a hardware issue at this point, but would like to confirm.

[lewis]

Hi，
Can you measure the voltage at this point? Please connect the battery and measure the voltage at this point in the picture to see how much V it is.

[krjohan]

Did you find a solution to this?