Guys, I have a problem with the CH2 front-end.
I have soldered wires to it, measured the output of the differential amplifier, the output of the fet amplifier, the pins of the TLV274 with another oscilloscope.
The most striking difference is the DC bias of the signal going into the FET amplifier. For the same reference 0V/3V square wave, for CH1 (known good channel), the input of the FET amplifier goes from -2.74 to -3.14V. For CH2 (known bad channel), it goes from -1.86 to -2.26V.
I understand the TLV274 is responsible for the DC gain and the vertical position as shown below:

However, what is not shown on the schematic is the TLV274 has feedback from the FET amplifier output (through pin 2). So, I don't know if the DC bias is bad because of the TLV, or the feedback is causing this DC bias due to a faulty component elsewhere (like the components of the FET amplifier).
Is it a good idea to remove the resistor 4M7 that injects the output of the TLV274 to the input of the FET amplifier, to test the amplifiers alone?