Dead Board?

[krab-skunk]

Hi, i have 2 ttgo t-beam lora32 868Mhz boards.

They worked fine for 5 months or so, but since today one board, stop working. What's not happening:

• not recognized by computer (using platform.io)
• the LED 1014 is not turning on anymore once the switch is set to ON.
• instead of 3.3V output on the board, i got 0.42V
• when a 18650 is installed and usb powered, no more red led showing charging

All i got is, once powered on USB, is a green led as per the picture: https://imgur.com/a/IgGZHNV I tried resetting it, nothing happened.

Is it dead or you would recommend me some things to try before throwing it, i have a multimeter but no schematic.

Thanks a lot

[SimonRafferty]

I had the same problem out of the box! The 3.3V pin header read 1.8V and nothing else was powered at all. The reason is that it has an AXP192 power controller to allow the ESP to switch peripherals on & off. Have a look at the AXP202X Library by Lewis He: https://platformio.org/lib/show/6657/AXP202X_Library

Add the following to your sketch: #include <axp20x.h> AXP20X_Class axp; And in Setup(): `
//Turn everything on axp.setPowerOutPut(AXP192_LDO2, AXP202_ON); axp.setPowerOutPut(AXP192_LDO3, AXP202_ON); axp.setPowerOutPut(AXP192_DCDC1, AXP202_ON); axp.setPowerOutPut(AXP192_DCDC2, AXP202_ON); axp.setPowerOutPut(AXP192_DCDC3, AXP202_ON); axp.setPowerOutPut(AXP192_EXTEN, AXP202_ON); axp.setDCDC1Voltage(3300); //Set Pin header 3.3V line to 3.3V. Processor is happy down to 1.8V which saves power

//I don't think this board has a built in LED, other than the Charge LED, controlled by this: // AXP20X_LED_OFF, // AXP20X_LED_BLINK_1HZ, // AXP20X_LED_BLINK_4HZ, // AXP20X_LED_LOW_LEVEL,

axp.setChgLEDMode(AXP20X_LED_OFF);

` Everything will come back to life!

It turns out the ESP will opperate down to about 1.8V quite happily.

It has a load of potentially useful (cool) features including setting the voltage supplied to any of the peripherals (to save power) and measuring the current supplied to them. You can detect whether the battery is being charged - and read the charge / discharge current.

People have commented that the battery doesn't cut-off when over-discharged. I suspect this needs explicitly setting up on this chip too.

[mattbk]

In case it helps, one of the lines above looks like it should be split into two:

#include <axp20x.h> 
AXP20X_Class axp;