This was quite helpful. I have a similar problem but with a solid state Fender Princeton Chorus and a faulty input jack. With your video, I think I may attempt the repair despite the difference in tube technology vs. a solid state board.
Nice video, only part I didn't like is you're avoiding the subject of 'how not to make this amp kill you' by plainly saying "only touch the parts around the input jack". I think that's bad practice, stimulating diy amp repair on the one hand but avoiding the most important subject on the other hand. I personally think it's your responsibility to teach people how to do this safely OR don't teach them at all.
I have a Red Knob Twin amp. Each of the input jacks work, but if the cables are moved slightly, the sound dies. I have to tap the cables into a certain place before the sound comes back again.