Sylvania 336mu

[Electronic M]

I don't have a feel for the relative brightness, but the max available brightness depends on the amount of HV you have and the CRT emission capabilities (ie how good the CRT tests), and how well the circuits driving the neck are working (and position of the ion trap if present). On most sets made after 1952 you should be able to watch the set in a sun lit room (pix may not be optimal in this case) as long as the sun is not directly shining or reflecting onto the screen....Less brightness than that indicates significant miss-adjustment, wear, or correctable defects.

It looks like you have very weak contrast. Is the contrast control maxed and have you adjusted the AGC control properly?