Philips TV unable to tune channels after repair attempt

[TheNic]

Hello,
I have a Philips 12TX3501 BW PAL TV (AC/DC) with TX3 chassis (https://elektrotanya.com/philips_tx3.pdf/download.html), and it had a strange intermittent contact issue. I resoldered many joints until I discovered a broken grounding trace on top of the flyback transformer that I fixed. I also cleaned all the potentiometers using a gentle contact spray (Teslanol T6).

After this repair attempt, I’m now barely able to tune in the channel from an HDMI to-RF converter (used for testing) which wasn’t an issue before. The picture is now rolling vertically from top to bottom.

I’m completely new to repairing CRT TVs and I only know the basics (like how to discharge the tube). Unfortunately, I accidentally blew the fuse while probing the area around TS421 with my ESD gloves.

I did several measurements using my MiniDSO, and the signals on pins 18, 21, and 23 all seem fine.
Where could this issue be coming from?

Here is a video of the TV's behaviour: https://youtu.be/PUL0uatmhak?feature=shared

Any ideas would be greatly appreciated.
Thank you very much!
Nico