3.3V line sitting at 1.53V

[MSATGroup]

I was using two T-beams with the display modules, and everything was working as expected. However, a couple of days ago one of my displays would not turn on. After investigating, I have found that the 3.3V line on this board is sitting at around 1.5V. The ESP appears to still be running, but the display won't turn on due to the low voltage.

I have tried using the code found at https://github.com/LilyGO/TTGO-T-Beam/issues/22

But this did not make a difference.

Any help would be greatly appreciated as this is my first time using these boards and I have never worked with a Power controller like this before.

Thanks

[lewisxhe]

Sorry, the 3.3V pin is controlled by AXP192, DC1, you should add the following two lines after initializing axp192 to turn it on

PMU.setDCDC1Voltage(3300);  
PMU.setPowerOutPut(AXP192_DCDC1, AXP202_ON);

[MSATGroup]

I'll give that a try justnow. Thanks

[MSATGroup]

Still no luck, 3.3V pin is still at 1.5V.

This is the sketch I uploaded. `#include

AXP20X_Class PMU;

// the setup function runs once when you press reset or power the board void setup() { pinMode(4, OUTPUT); PMU.setDCDC1Voltage(3300);
PMU.setPowerOutPut(AXP192_DCDC1, AXP202_ON); } `

[lewisxhe]

You have not initialized the PMU, I have added instructions in the sample code, please refer to here:

https://github.com/Xinyuan-LilyGO/LilyGO-T-Beam/blob/866e164ee08b4c7a0263ceaf801e87afadcf0140/examples/ArduinoLoRa/LoRaSender/boards.h#L55

[MSATGroup]

Hi, I ran the example code LoRaSender that you linked, and the LoRa module is sending correctly. I can receive the LoRa packets with my other T-Beam.

However, it hasn't solved the issue as the 3.3V line is still at 1.5V

Could it be that the PMU chip isn't working correctly?

[lewisxhe]

You can use PMU.getDCDC1Voltage() to view the returned voltage!

Then you can use

PMU.setDCDC1Voltage(1800)
Serial.println(PMU.getDCDC1Voltage());

If the set voltage does not match the read voltage, it may be broken.

If the setting is the same as the read voltage, but the actual measured voltage is different, then it is also broken!

You'd better take a picture and show me where the voltage is!

[MSATGroup]

Hi,

I added these lines, but I appear to be getting a random number from the PMU:

Edit: The voltage on the 3.3V pins is reading 1.53V

Any ideas?

[lewisxhe]

Unfortunately, it is damaged.

[MSATGroup]

Okay, It appears to only be the 3.3V line that is affected for now. I'll keep using it for testing and will keep in mind that I can't use the 3.3V pins.

Thanks for your help.

[lewisxhe]

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