It is possible to adjust the capacity of C3, but not C5.

[moyaelectronnka]

Hello. When setting up the oscilloscope at a level of 0.1 volts with a capacity of C3, everything is fine. However, after switching the test signal to 3.3 volts, problems begin: with an increase in sensitivity, the beam disappears from the screen. What could be the reason?
Thanks.