ESP8266 Community Forum

- Sun Mar 05, 2017 6:30 am #63366 I've got a strange issue with esp8266 wifi connectivity. I got 10 board's manufactured with esp8266ex on it. These are the QFN32 package ic's and not the pre-assembled boards like esp12E. I am facing issue with 2 of my boards. I am not able to connect to my wifi on these two boards, everything else works fine.....bootloader message, terminal output, burning new code etc etc, But the wifi part is giving problem, also connecting to esp's AP is bit problematic in these 2 boards ( I do get connected eventually, but I takes 4-5 tries...sometimes even 8-9). I am not able to figure out what the issue is.

The other 8 boards are working great. There are able to connect to my wifi, I can easily connect to their AP.
If I try to run a wifi network scan code on my faulty boards, they only detect my home network like once or twice in 20 - 25 scans, but their were two networks which were more than thrice the distance away from my own router, but the esp would still discover it every time. I then tried to connect them to other network but still they couldn't connect.

I am not able to figure out why is this happening.
1. I am able to get response from the esp, means that my hardware it working fine.
2. All other modules are able to connect to my router. Means their is no issue with router channel or anything like that.
3. No scratches on PCB
4. I though that I might have had a loose solder joint while soldering, so i re-soldered most of the parts.
5. While working with a faulty board, all my other esp's are disconnected, so network is also not populated.

Does anyone known's a possible reason of this problem and can help me solve it.
Thanks in advance.

- Sun Mar 05, 2017 8:43 am #63370 When you were able to do a WiFi scan, what signal levels did you get on the bad boards compared to the good boards?

My first guess is a bad capacitor in the antenna circuit. But I don't know what you have done in your pcb layout. Could you give more details, maybe a picture, a link to the schematic you used?

- Sun Mar 05, 2017 9:44 am #63373 Oh, yeah.... nice idea....I should have tried that. I'll run the scan test on another board tomorrow and will share the results(Unfortunately, I won't be able to do that today). Bad capacitor, I doubt that, I have used 5.6pf NP0 capacitor in my antenna trace, but you never know, their is always a possibility, I'll replace that and give it a shot.
Schematic, I downloaded from nodemcu's github repository. (That too, i'll be able to provide tomorrow only).

Anyways, thanks for the suggestion. I'll try it and update you

- Sun Mar 05, 2017 11:01 pm #63397 Now I have another issue and don't have the strength left to resolve it.(Guess I'll just replace the ic, and hopefully everything will work)
So I was trying the solutions discussed earlier. Replaced the capacitor (well, at-least, I was now able to connect to esp AP easily). Powered up esp, compiled the wifi scan code and it won't upload to esp now. I opened up terminal, getting the boot message, my previous code's serial output, I put it back to bootloader mode, that message is also displayed correctly, but the code just won't upload. No other terminal is open in background. Checked the wire's with continuity test, they are also properly connected.

The only issue I can thing of now is that I might have partially damaged the ic while soldering it to the board ( due to overheating). But I don't know if that can create these kinds of issues or not, as I am getting serial output

Guess I'll just buy a new IC now.