Fixing electrodragon SPDT double relay board

Got Electrodragon’s SPDT double relay board from Santa :)


First bug – one of the relay contacts has wrong setted plate.


2nd bug – very bad wifi connection.  Router logs: “MAC@wlan2: disconnected, extensive data loss”

After few hours of experiments: power supply has burned out AC wires. There is no fuse. At all.
Thanks to thin wires – they have made all fuse job.

ESP8266 is alive so  I’ve remove AC Power supply from board and continue experimeting.
It works only in 1m range from router. Strange.

Other ESPs (nodemcu board) are working fine without any problem. Very strange.

Also, I need ADC input in my project but it gave always 1024. And there was +5v on ADC connector on board ( ESP8266 allows 0-1V at ADC input )

So, I removed ESP from PCB. And here it is – soldering bugs between 2nd and 3rd pins.

Also there is wiring bug – 2nd pin ( ADC ) – is connected to 5v tansition wire for relay.  So the problem was here.
Gently removed track by knife and ADC is free!

Pull-ups for GPIO4 and IO5 should be 3.3k according to wire diagram

But there are installed 4.7k. 1-Wire Dallas Themp sensors working unstable, loosing data from time to time.

Soldered ESP board back to PCB and now it working fine. 20m+ from router – 70% signal power.

Soldered back Power Supply.

Now board is ready for production use.
Conclusion: +5v making ESP crazy ;) be careful.

2 thoughts on “Fixing electrodragon SPDT double relay board

  1. Сложно сказать, насколько именно здесь есть проблема с подачей 5В, но у меня ESP вполне уверенно работают на этом напряжении (и кстати, несмотря на кочующие с сайта на сайт страшилки “от 5В она сгорит”, сам производитель вполне допускает 5-вольтовую работу)

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