WT32-ETH01 hangs on boot after PSU power up

I’m currently working on a solution to power some SK6812 LED strips using a WT32-ETH01 Board which has an ethernet port I intend to use to improve reliability of my lighting.
I am using 2x 470 uF Capacitors with a 8A Fuse (which matches max output for my currently used PSU) for shared power to the strip/ESP32 and a 68R for the data line. PSU is Meanwell LPV-60-5. This seems to be in line with the recommendations and I expected it to work. It does, kind of, until the PSU loses power from a switch or outage or whatever and you want the ESP32 to come back to life.

As soon as my mains power line to the PSU is cut, the ESP32 on my board refuses to boot up after mains power is restored unless 5V line is also cut and restored after PSU power up. I suspected an issue I had read about GPIO12 and flash memory set into low power mode causing a brownout on boot but this does not seem to be the issue.
This also happens when the ESP32 is directly connected to the PSU, though not all the time as oppsosed to my full wiring, I assume capacitors are responsible for that.

ESP32 NodeMCU as well as any ESP8266 I tried show no issues at all using the same PSU.

I now suspect the voltage ramp up to be too slow, causing the ESP32 to brownout on boot. I’m not much of an electronics guy so I would not be able to make accurate measurements, I just used a cheap multimeter seeing 5V output at 4.6V before going to 5.15V. From what I have read, ESP32 might be a bit sensitive to low voltage on boot and this board in particular has to power not only the wifi module but also the ethernet module. For me this would be more of a timing problem than an actual problem with the voltage but this behaviour does counter my goal to improve reliability using ethernet.

Question is, do you think this issue could be resolved with another and hopefully more quality PSU? I haven’t tried disabling the brownout protection entirely which doesn’t seem to be a good idea anyway. As long as I can make the ESP32 boot, it works flawlessly.

I already have another PSU on the way but you guys might have another idea I haven’t thought about yet?

I mention this as you seem like you want to hardware tinker and are capable of doing so.

As a test, find a broken toy with 3 AA battery capacity so you can harvest the battery holder. Stuff it with 3 AA’s so you get ~4.5VDC output. Don’t have the LED strip +5V powered / connected to anything. Just the battery box and the esp32/esp8266.

Now use the battery box and connect to your esp board. If it powers right up without a problem every time you test it, just the next test - which might bork your board, but not likely. Wiggle one battery in and out of the holder so it makes and breaks contact very quickly. That capacitor should hold up the voltage a little, but at some point it will droop too low and power off and immediately restart the esp when the battery makes good contact again.

After doing this a few times while observing the NodeMCU’s on-board LEDs, you should have a feel for whether it boots, or hangs, and maybe have a feel for how to prevent it. You can test it right away with the battery holder. You can try a push type toggle switch to toggle the power lead if you want a little more consistency in the on/off/on times.

I have been doing something similar with the 5V output, though not battery powered. Until now my only finding is, the Board boots every time, as long as the PSU has been powered on about 1s before connecting 5v to the board. Thats why I assumed there might be an incompatibility with this type of PSU.
I might try with batteries to see if it has any effect, I assume it will boot just fine.

Second PSU didn’t help. As this was the same type and vendor, just with slightly different specs I now have ordered yet a third PSU which also allows 5v voltage regulation. I have also ordered another Board from China to double check if theres an issue with the particular one I am using. But I’ll have to wait a few weeks for the board to arrive.

Some more info here. I read through this thread: Due won't start after power off-on, have to reset - #88 by renatodnts - Arduino Due - Arduino Forum
That gave me the idea to simply connect a capacitor between EN and GND which effectively delays the time to reset on boot. That actually helped. I ended up using a 470uF cap, 100uF did not seem to be enough. There is a very noticeable delay, maybe 1.5 - 2 sec and the boards boots just fine, no matter what I do with the PSU on mains side. Problem solved for now (don’t mention my soldering skills…).

I wanted to see if I could solve the problem not in hardware, but in code (as proposed in the linked thread as well) and therefore compiled WLED with a 1000ms delay in the setup function.
Then I proved myself an idiot. Just as I wanted to flash the custom compiled firmware I accidentally missed the pins for 5V and GND by one and saw the boards VRM go up in magic smoke. Damn, I really should stop late night tinkering with electronics…
Good news is, I might be able to get my hands on another board faster than I thought. Will keep testing.

Read through this Power supply for the ESP32 - #6 by Andreas - Stromversorgung / Power supply - Hiveeyes
and what i experienced seems to be a very common problem with ESP32 boards for which the best solution seems to be the capacitor I added. Not sure why the vendors couldn’t address this with a tiny smd cap on the board but at least I can get the board to boot now.