What component is this? Device heating up and using 200ma

Using the Meshtastic Starter Kit with the most recent Meshtastic firmware. Device drawing 200ma - unclear why. Heat appears to be radiating from this component (or nearby) regardless of whether powered via USB or JST.

Looking for a fix because I got this for the lower power use, and I imagine the device will give out soon enough.

. Any ideas?

Second question / a bit of rant:
I love these devices on paper but I’m a bit frustrated. I fried two of these boards - that was entirely my fault as I had inadvertently used two 18650s in series (which I thought were in parallel) and which had worked on my firebeetle, I assume due to greater voltage control. I ordered two more - one was DOA, and the other has this issue. I want to order more but this is becoming expensive…

The other question I have is about whether ordering on directly on this website would change the potential import fees. On aliexpress, I’ve had no issues, but with other retailers shipping from China, often when I order directly from the website, I get hit with tons of fees (usually due to fedex, UPS, etc). [EDIT: Ordering from Canada] If I order direct, would that be an issue? There’s just greater selection ordering direct and I have a few other things I’d like to do with these boards (I love the power consumption on them, I typically use ESP32s and this is like a whole new world for me, even if I’m disappointed about the tolerances on the baseboard).

Welcome to the forum @PlantsThatsWhatsUp

That component is the Dual 0.7-pF, 3.6-V, ±8-kV ESD protection diode with 5-A surge rating for USB 3.0

It should not get hot at all, it is “just” protection of the electronics from voltage spikes on the USB lines (static discharge e.g.)

Voltage range of the battery is defined in the datasheet of the Base Board, 3.7 to 4.2 V, commonly known as 1S.

Is the 200mA with just the WisBlock Base Board and the WisBlock Core module? Or do you have other modules plugged in?
You mentioned ESP32, are you using the RAK11200 WisBlock Core module?

Regarding resellers in USA, please check our partner Rokland

I found that on the bottom side of the Base Board is the 3.3V voltage regulater (below the TSV diode) and I am guessing the heat is coming from there.

If you are using RAK11200 (ESP32) its startup power consumption is at the limit of the voltage regulator. I do not know whether Meshtastic is using the low power modes of the ESP32.
What Meshtastic role did you set the device to? Modes like Router/Repeater are the most power consuming modes and that could lead to the consumption and heat dissipation

Thanks for the quick reply.

  • I’m using RAK19007 + RAK4631, and that’s what’s pulling 200ma (measured via USB multimeter which has been otherwise validated).

  • Not using any other modules.

  • I’m not using an ESP32 module at all, I just meant historically in my other projects.

I think you’re right that component isn’t the issue. I forgot to check the back. My thermal camera is fairly low resolution, but the heat appears to be coming from here - it’s hard to pin point the exact component.

Re: Resellers - I’m in Canada. I’m just worried about the shipping being different than AliExpress as FedEx and them play the whole import fees ‘service’ charges game. Looks like my options are to risk those fees, or accepted limited selection on AliExpress?

EDIT: Just saw your edit, that sounds right. Can you link the regulator? I’m wondering I have a drop in replacement lying around. Long shot, but yknow, feels bad. I narrowed the heat to the component labelled “C37R44” or the one directly to its left. Is that it?

I ended up finding this image that labelled the component:

After looking it up - you’re right that it is the voltage regulator. I don’t have a replacement but I may try swapping it from the dead board I received as I imagine if it’s heating it is a matter of time before this board dies so I might as well try.

As for the shipping issues, I guess I’ll just hope that the AliExpress store eventually gets some additional base boards listed (hint hint) as shipping through FedEx is brutal and I’ll end up paying a ton in fees which I swore I’d never do again last time I fell for their shenanigans. I should probably take a break since I’ve now spent $150+ on dead boards (two of which were entirely my fault).

Blah - a disappointing evening all around, but I gotta say, your quick answer and analysis is the highlight of this whole otherwise brutal experience so thank you, it is appreciated.

I suspect the 3.3V voltage regulator:

But I don’t think manual replacement is possible (unless you are really good)

Is this problem on a single Base Board or a single Core module?

And, just to take out Meshtastic from the equation, can you flash the attached UF2 file and check the power consumption?
It is a doing-nothing-low-power example I wrote for the RAK4631.
WisBlock_LowPower_V1.0.0_2024. (149.1 KB)

Usual steps to flash
(1) get the UF2 file from the attached ZIP file
(2) double push reset button to get the RAk4631 as an external drive RAK4631
(3) drag the UF2 file to the external drive

Thanks - I’m not sure which component it is as I have not done any swapping across my boards. I suspect it’s the baseboard rather than the core given the heating issue. The other device I have doesn’t work so I’m hesitant to swap even if this one is likely going to give out soon enough. I uploaded the code you shared which used slightly less power around 192mA.

If you just bought the boards, please contact us through [email protected] for a replacement. Something is definitely wrong with the base board. The test code I sent you should go down to uA’s.

Thanks for all your troubleshooting help. Just FYI, I emailed both [email protected] and [email protected] 6 days ago with a link to this thread and never got a response so I imagine that’s that.

Should not be like that.
Did you get any no response at all?


Can you send me your email address as private message. I will check our support help desk.

Thanks for all your help / updating for readers. All resolved, beegee went out and found my customer service thread before I could even provide my email!

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