Only vertical lines are distorted and move slightly in an apparently repetitive rhythm
Bad Capacitors, particular check the seconrary polymer types, testing for leakage current, self-inductance and component quality.
Replace the bad capacitors to the correct types. Important:
Important to note that not every capacitor is suitable due to its key data and size. It is essential to ensure that the correct specification is used!
This is an unpleasant defect, because there can be several reasons for it. First of all you should check the power supply of the VSA100 chips. Test if the power supply still works on both channels. Check the ripple of the DC voltage on the secondary side of the power supply. This can only be determined with an oscilloscope and also please check, if the voltage on the primary side is ok.
Check if the two coils have a clean magnetic field spectrum. This can be seen very well with a spectrum analyzer and a HF-Probe.