DSO Shell was designed for low voltage measurement. The maximum input voltage was specified as 50Vpk (peak value). So it can not be used to directly measure any voltage higher than 50V.
But by looking at the schematic:
We can see there's no division at
50V * 5.1M / (510K + 5.1M) = 45.455V. While the TL084 Input voltage is only 15V.
Am I missing something? What's the maximum input voltage for this scope?