JD0171R (R for red) small 3-digit 7-segment voltmeter schematic

So yeah this one can be had for less than a dollar from aliexpress or similar in various display colors, mine was red. It was a 2-wire model but as can be seen from the schematic it is trivial to change it to 3-wire operation if needed (remove the SMD resistor with 0R on it and solder a wire).

This reverse engineering was done thinking i could maybe reuse the assembly and swap in a different MCU (this chip has no markings, and no obvious way to access it, thus i guess it is mask rom or similar), but it is being a bit of a challenge to find an MCU with a suitable pinout & package.

The other side of the PCB has the text SJ-DC028-AB and the 7-segment display says YU2?81BS (? = 3 or 8, not sure).

The ???-resistor was likely a resistor (hypotethically could have been a cap...), but i managed to destroy it when disassembling this, so no value known.
That resistor and the 180R resistors (made of a 4x pack and 4 individual ones, what) are between the PCB and the 7-segment. Rest of the components are accessible for fun and mods :P

Oh yeah and Vcc is 3.3V, the 0uF cap is a place for a cap, nothing installed.