@m5stack i finally had time to check the schematic. I've found a really, really strange thing: the pin 8 of the IP5306 (U3) is not connected with the +5V netlist! So i checked with the tester and it's true, there is not connection between the pin and the netlist. What is the usage of the IP5306 if it's output is not connected to anything?
So i tried to connect with the +5V netlist (i soldered a small cable to connect pin8 and the +5V pin of the m5stack bus) and now it works like charme!
At the moment i have only tested without battery (i desoldered it some days ago and i have to resolder it), but please, can you explain me this situation? Now everything works fine, led bars, microphone, anything, so there is a real issue with the schematic of the base or am i missing something? Please, explain

@liemph and @ajb2k3 thank you for your feedback.

@m5stack do you have any answer about the problem? I think it'd be nice to give us a feedback, don't you think? There is a problem in the base board schematic? How can we fix it?

@liemph this is very sad... @m5stack how is it possible so many bases have this kind of problem? there is some way to fix it? Can we modify the board, soldering/desldering some component?

anyway @liemph, can you tell me where did you bought the base-x? It could be a good replacement, i've bought m5stack for my son and without the base is almost useless for him, thank you

@m5stack the voltage of the battery is 4.1V, so it works properly. The situation is the same for @liemph the core only works without the base containing the battery, so i don't have the battery, the additional ports, the led bars and the microphone, so, why i bought the fire model? When i'll have time i'll investigate further but i'm really discouraged...

@m5stack after further investigation the problem seems to be the battery module, when i use the core with usb it works, but as soon as i put the battery it stops working. Can be a problem related to the IP5306? It's possible to have the schematic of the battery module of the fire core?

@felmue sorry, i don't want to be rude, but did you read my post? The device doesn't even turn on, how it's supposed that i could use ui flow? When i click the power button i ear a noise and nothing happens. This problem occured with two different devices bought from different vendor, so i just would like to know: it's a known issue or it's jist me unlucky? There is a way to solve the problem? Since i am really disappointed with the fire model, the other models have the same hardware or maybe have a different design? Thank you

@felmue both device are m5stack fire, i tried both usb and battery, the firmware is the original ui flow. With the second device i was not even able to flash any firmware, with the other one, i just flashed some led blinking test, always using ui flow. Then both devices died. Frankly speaking, if there is an hardware issue with the fire model it'd be better to say clearly. Two hardware faults (same problem!) on two devices is simply unacceptable!
Just to know, other m5stack models have different hardware or the hardware is the same than the fire model?

Hi, i have bought an M5Stack from Amazon, after few days it stopped working. It played a white noise anytime i clicked the power/reset button but never turned on again. So i bought another one from Digikey, it worked just few minutes and... same problem! Just a little bit different... sometimes it works, sometimes it don't, if you're lucky it works, otherwise it just make this creepy sounds and doesn't start (90% of times i try to use it, it doesn't work). Are you serious?! Two different cores, from two different vendors and i got the same problem?! There is something i'm missing or this is the way this product should work?!