1956 Packard Bell 21DK1 with raster but no picture

[Electronic M]

Yes was referring to paper caps...Be wary some masquerade in plastic shells either tubular or the sneaky ones that look like (and sometimes are listed like) the *reliable mica dominoes. *Mica caps do tend to fail in sweep circuits due to the stress those circuits tend to place on them.

The right metal can is just a safety cover/electrical noise shield over the flyback and HV rectifier...You can remove it to replace that tube and perform other service tasks if you wish.

Interlocks invaded nearly ALL radios and TVs before the 60's, and TVs were early adopters due to fear of the potential dangers HV.

Some 50's sets had suction cups, but it was not until ~1960 that it became close to standard.

There should be a shield on the tuner underside that can be removed to access the contacts so that you can clean them (your initial post suggests to me that they are dirty).