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Low voltage on 3V pin of ESP32 feather
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Please be positive and constructive with your questions and comments.

Low voltage on 3V pin of ESP32 feather

by geoff2802 on Sun May 02, 2021 7:44 pm

Hi all,
New to this forum. I have a new Adafruit ESP32 feather, sourced from Mouser.

The voltage on the 3V pin is a constant 1.36V. Why would it be so low?
The USB cable is plugged into an iMac. Voltage at the USB pin is 5V, as expected.

Photo attached.

All assistance appreciated!
Cheers
Geoff.
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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Sun May 02, 2021 7:51 pm

bit more info... the yellow LED on the board is constantly on while powered with the USB cable.

BTW, I haven't been able to my iMac (OS 10.13) to keep the CP210x kernel extension loaded (I did successfully install it and it is loadable). Issue raised with SiLabs.

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Re: Low voltage on 3V pin of ESP32 feather

by adafruit_support_mike on Mon May 03, 2021 11:32 pm

geoff2802 wrote:bit more info... the yellow LED on the board is constantly on while powered with the USB cable.

You can ignore that.

The LED is connected to the onboard LiPo charger's status pin, and the charger's status can change randomly when no battery is attached. It doesn't mean anything beyond "I don't see a battery".

WRT the low voltage, it sounds like something has failed. Is any part of the board getting hot?

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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Tue May 04, 2021 3:58 am

Hi Mike,

Thanks for your response.

No part of the board gets hot even after 10 mins powered by USB. It's barely even warm to touch.

Cheers,
Geoff.

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Re: Low voltage on 3V pin of ESP32 feather

by adafruit_support_mike on Tue May 04, 2021 10:33 pm

That's unusual. Low voltage usually means a shorted component somewhere.

As a sanity check, measure the voltage between the pins on the RESET button, up near the USB jack. See what you get there.

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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Wed May 05, 2021 3:54 am

Hi Mike,

There is also constant 1.36 volts measured at the two pins of the Reset button.

I can't see any evidence of scorching on the board.

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Re: Low voltage on 3V pin of ESP32 feather

by adafruit_support_mike on Thu May 06, 2021 1:29 am

Thank you.

Something is definitely out of spec in that board's power system, and finding it isn't worth making you wait any longer for a working device.

Contact Mouser with a link to this thread, and let them know we've approved a replacement. They're good folks, and will get you a replacement.

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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Thu May 06, 2021 2:13 am

Hi,

Thanks Mike; I appreciate your help.

I reached out to Mouser earlier and have a contact for the case. I've sent them a link to this thread and await reply.

Looking forward to getting on with my project which involves AV and lighting automation.

Cheers
Geoff.

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Re: Low voltage on 3V pin of ESP32 feather

by adafruit_support_mike on Thu May 06, 2021 3:11 am

Cool. We love to see build descriptions and project pictures if you want to show off. ;-)

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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Thu May 06, 2021 3:22 am

Quick response from Mouser - a replacement board is now on the way.
Good service from their customer service team in HK.

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Re: Low voltage on 3V pin of ESP32 feather

by geoff2802 on Mon May 10, 2021 8:55 pm

The replacement board arrived from Mouser today and it is functioning as expected. Voltage correct and a test sketch runs as expected.

This also resolved the behaviour I was seeing whereby the CP210 driver wouldn't stay loaded into the Mac OS kernel (I had to load it manually). The Mac couldn't see the board of course, because there was insufficient voltage to power it. SiLabs was assisting and I've recorded the resolution on their customer forum so that others may benefit.

With both problems solved I now can get on with my project. Excellent.

Thanks for your help Mike - this is appreciated!

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Re: Low voltage on 3V pin of ESP32 feather

by adafruit_support_mike on Mon May 10, 2021 10:57 pm

Glad to hear things are working for you. Happy hacking!

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Please be positive and constructive with your questions and comments.