EDU09 output offset


I recently bought the EDU09 Oscilloscope kit from Velleman. The calibration process works fine, but there seems to be a DC output offset.

When connecting a 10V DC source, the oscilloscope measures a voltage just below 5V. Also, when connecting the probes to a 1.5V battery, to perform the advanced calibration, I was only able to adjust the DC mean between -0.2V and 0.2V.

Voltages on IC2 and IC3 correspond to voltages already mentioned on the forum.

Can someone help me with this issue.

Thanks in advance.

Please check the test leads for continuity.
It seems there may be missing or bad connection.

Please test: Is this (-0.2V and 0.2V) the result on 0.5V/div range if no battery is connected and the test leads are connected together?

Thank you for your response.

The issue was a bad solder between R28 and R24, which resulted in an excessive voltage at pin 1 of IC1. This is solved now and the EDU09 works perfectly.

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No problem. Glad you resolved the issue.