[compucat]

Definitely start with the power supply. i too have a 25MC33 Zenith roundie and the electrolytic caps in the power supply are old enough now to cause trouble. This set should easily be able to produce 25 KV of high voltage which is what it should be adjusted for. These sets are full of brown drops which I'm not sure if they should be considered for replacement. My set still has most of them and I suppose one day it will need a full recap. Mine is in regular service and the only issue I have is the vertical acts like it is going to fail sometimes. I have not figured out the cause yet. The picture quality on these sets is fantastic, though, well worth the effort of a good restoration. Follow all the setup procedures in the Sams after restoration and you will be amazed at the performance.