When I powered this module with a 12v power supply, the AMS1117-5 burned out and then the WiFi Kit 32 board turned unresponsive.
Looking at the schematics, it looks like the Fuse shouldn’t be failing because is used when powering from USB and I was injecting the 5v from AMS1117-5 directly to the +5v pin on the WiFi Kit 32 board, not passing by the USB.
Now, when I try to power on the board from USB or from +5v pin, nothing happens.
I suspect from the ESD Protection diode RSB6.8S but I cannot find it on the board. Could be this component the cause of fail?
But also I have seen that the ESP32 works at 3.3v and it looks like the CE6260 Mosfet is the responsible of providing the 3.3v. When I power the board from USB, I can measure 1.96v in the +5v pin. And it looks like there is continuity between +3.3v and GND pins.
I have made a test. I have powered the 3.3v pin with 2x1,5 AA Batteries in serial and still is unresponsive but I noticed some heat at the LTH7 (it looks like a lithium charger) that it is between the USB connector and the display.
Is possible that this one was burned when the AMS1117-5.0V blowed up?
Should I test any other component in order to find the failure?
I cannot find the CE6260 on the board. I have identified several 5 pin smds like A19T (TRANSISTOR SMD MOSFET AO3401 A19T -30V -4A 1.4W Canal P SOT-23) and LHT7 (Lithium charguer) and there are two more that I cannot find references. Both are in the bottom side of the board, one says “ZTt” and has 6 pins and another one says “9A26” and has 5 pins.
No, The ASM1117 5.0v was an external module that I was using in order to power on with +5v the WiFi Kit 32 board and was working ok for 1 month.
This was the fried module. The ESP32 board doesn't has any component apparently burned to the eyes but after the ASM1117 failure ceased to respond.
SORRY!!!!!
I have made a new test. I put 3,3v on the pin2 and GND and now it is working!!!!
But I disconnected because a component is taking a very high temperature on the board. This one:
The regulator chip, TP4054 U2 which is rated to 6.5 V absolute maximum so no doubt "disapproved" of the 12 V supplied when your AMS1117 failed and shorted through.
I removed TP4054 chip. Connected the USB cable to see what happens: Nothing. Dead.
Powered up with 3.3v in the 3.3v pin and it worked for a few seconds (more than 15s.) and then stopped to work. The USB TTL 3.3v adapter which i was using turn off the led when I power up the board. Looks like there is a short but I don't know where to start by.
If anybody could help me would be great
Sadly, those kind of problems are hard to fix even with a full lab or repair workbench in front of you. Remote troubleshooting is almost out of the question.
Even if you make it work, the reliability is compromised, you will never be able to fully trust it to remain working.
As aarg says, over-voltage events are likely to cause a cascade of failures, complete and/ or partial. It seems you no longer have a device that is in any respect reliable.
