Incorrect behavior of sen2

[droppedonmy]

Hello everyone,

First off I'd like to thank JYEtech for their awesome oscilloscope.

I have an issue with the sen2 button not working correctly. Instead of changing the signal sensitivity, it changes the voltage of the trace.
It seems that increasing sensitivity instead increases the trace voltage by 10V increments.

Testing the fault condition I've tested this scenario:

CPL set to GND
Sen1 set to 1V

Switching positions on Sen2:
x1= scope shows -18V
x2= scope shows -11.2V
x5 = scope shows 0V

it should show close to 0V throughout but deviates.
Also, the reference voltage on the bottom left of the screen does not confirm 5x sensitivity, instead it stays on 2x.

It seems to be glitching between 5x and 2x settings, and therefore I still suspect this is bad soldering or maybe a faulty component.
I have re soldered board components involved in the circuit, however the error persists.

I'm wondering if anyone can shine some light on which part of the circuit is causing the sen2 button to act this way.

Edited for clarity

[davef]

I am just checking that you have performed the "0V Line Alignment" as in User manual page 3.

If you can't get a change in the screen readout between X2 and X5, maybe checking VSENSEL2 on pin TP8 might help.

Good luck!