I would check the battery cable has the right polarity. Maybe it is backwards? (-) is to outside of pcb edge.
I checked. Polarity is good.
Did you order these from the KSGER store, or some shady dark alley? Sometimes I think they ship different quality boards.
They are from KSGER stores (there are 2-3 stores on Ali).
This Ve2.12S board has the mystery op-amp "621K" that the Russians have problems with, low accuracy on temperature. What does it report for H/W and S/W version?
As i remember, it's just the usual H/W 2.0, S/W 2.12, MCU STM32F103 (now can't check it anymore). I had it connected in the past with ST-link without problems.
Can the op-amp be replaced with the 8551? I ordered a few pieces.
Thanks for the Ve2.12S pictures, another schematic to draw lol.
We'll do it, friend! I have more accurate pictures, will send you over if you want. I think is a bit different (or not) from your Ve2.12S.
After disconnecting the battery, the controller does not work?
No. Only the LED lights continuously after 2s from connecting the power and no tip connected.
Maybe you have a large static charge on you and damage the MCU with it?
Or when connecting the board bent and damaged the soldering.
I don't think i had any static charge, because in same time i played with the black board and he's ok. Anyway, i didn't touch the MCU.
Have you checked the power supply?
Yes, i have 3,3V on MCU.
But interesting is, i have only 1,4V in battery connector (without battery connected). On the good board i have 3,3V in it.