ESP32 Forum

Hi,
I confirm that some S2 Mini clone boards have a routing problem on the C14 ground pad.
After several hours of investigation (and one jeopardized board) the fix is straightforward.
Scratch the ground plane a put a blob between the C14 cap and the ground plane. See attachment.

The WiFi is now rock solid and stable, this make a huge difference.

Cheers.

hi even after adding the blob mine have same issue

Hi,
I confirm that some S2 Mini clone boards have a routing problem on the C14 ground pad.
After several hours of investigation (and one jeopardized board) the fix is straightforward.
Scratch the ground plane a put a blob between the C14 cap and the ground plane. See attachment.

The WiFi is now rock solid and stable, this make a huge difference.

Cheers.

hi even after adding the blob mine have same issue

This fix didn't work for me either. I added a larger cap between en and ground by the RST switch which did work.
I verified that the EN line voltage was very choppy before this mod using a scope, afterwords it was smooth and no more random resets while using wifi.
https://esp32.com/viewtopic.php?f=19&t= ... 10#p106290

I confirm that some S2 Mini clone boards have a routing problem on the C14 ground pad.
[...]
Scratch the ground plane a put a blob between the C14 cap and the ground plane. See attachment.

The photo in this post seems to show more bad solder joints.
Resoldering them might help, or simply buy another board.

To anyone still having issues with s2 mini (s2 not connecting to router etc). The main issue is External crystal circuit. The load capacitors are most likely wrong values or bad. With an oscillascope Gnd connect to esp32s gnd then touch the probe(x10) to either C1 or C4 capacitors conneced to either Xin or Xout of crystal and the wifi will magically connect to router/phone etc.

You can also bootleg "fix" it by connecting a pullup resistor to the cap connected to Xtal N if you dont have caps.

The datasheet states that the crystal must atleast give more than 500mV but on this board Xin Output range 410 -880mV and Xout as low as 120mV - 215mV . ON GOOD working dev boards from esp32, esp32 s3 and esp32 c3. the voltage range from crystal is 680mV to 1000mV.

Another issue is the last capacitor on Antenna trace path. Possible bad or wrong values also.

Great to see so many solutions being shared! For anyone still struggling, it might help to check the grounding and capacitors. I had similar issues with reboots when using WiFi and found a stable connection after adding a larger capacitor between EN and GND. Another simple fix is lowering the WiFi TX power slightly — this helped eliminate reboots for me.

Also, if you're in the mood for a break from the tech talk, here's a bad dad joke to lighten the mood:
Why don't skeletons ever use WiFi? Because they don’t have the guts to connect!