Bad Tube or Component?

[Electronic M]

Many hum symptoms are cap related. If the bottom of the raster rolls up the cathode lytic on the vertical output is probably bad. if the deflection is grossly off freq it is probably caps and or resistors...Possibly just an adjustment, but not often.

Worth doing if you can see all tubes in a set is to look for 'white caps' if the tube cracks and loses vacuum the getter (which is a dark blotch inside the glass usually on top) will turn chalk white.


I don't troubleshoot based on what type of part much, instead if you have something on screen or don't it will usually point you to 1-2 stages (circuits around a tube) that usually only consist of a hand full of parts to check (sometimes voltage checks in the sections will narrow it MUCH further)... Look for a block diagram of a TV set and try to understand how all the blocks add to the final output...When you know it is easy tie symptoms to the block responsible for that aspect.