If you first change caps and it helps, it is possible you solved the real problem partial or temporary (example: by bending some wire with a very bad solder joint that now makes just enough contact)
This is the main reason why I advised to first measure in the scope (you can solve the fault temporary but also make it worse)
It could be you have a dodgy solder contact somewhere. Use a strong loupe to check them all. For most the ones that have moved while you cleaned things.
Check you power rails. If it was not used a long time it is possible one of the electrolytics was leaky thanks to a bad oxidelayer and now shorted out. They are big so they can cool them self enough to do that for some time (a small modern cap will overheat and then blow up much faster)
What did you use for cleaning and how did you apply it ? If the stuff is conductive and you spray it all over the switch and pcb, chassis etc you can get leak currents.
Be aware that you have contact cleaners that need to be removed after doing there job and some do not clean but only lubricate contacts, some do both. I always use K61 but there are others. If that does not help I use K60, but only if removing the switch is a hell of a job and I can remove the K60 after cleaning. If possible I remove the switch and clean it with K60 and after that it goes in the ultrasone cleaner.
This can be hard to find. I had an measurements-amplifier here that gave errors sometimes. It was already returned to the factory but they did not solve it. I was checking every solderjoint and removed all boards to check (but still connected so I could move wires, bend things, knock on things etc to see the response)
There was one tiny board left on the frontpanel with a header for a piece of flatcable going to the LCD pcb a few cm away that I also left in place because that had no problem.
I wanted to make a note but could not find my pen. I lifted one corner of the amp cabinet to look under it and the amp gave its error message. Every time if I lifted the cabinet on that same corner the error appeared. Turned out there was one pin of the header on that small pcb not soldered at all. I could not believe that such a small force on such a heavy frontpanel could influence the contact but it did. I had the amp 2 years later again on the bench (but now something completely different)
And the customer told me it worked perfect all the time.