I just saw this video. I think the U1 "microcontroller" you are pointing to is actually the HY3131 DMM front end (48 pin). The NCs pins seem to line up. The pins you pointed to are AGND, REFO and VSSA on the front-end. The location of Xin/Xout seem correct and the HY3131 spec sheet specifies that 4.9152 Mhz Xtal. Perhaps U16 (64 pin) next to the buzzer is the microcontroller? Maybe U16 is a HY16F 32bit microcontroller? - Phil