Hi Don,
First may I say thanks for your advice. I have read many posts on the forum and have learned a lot from yours and other member posts.
The predicta ones are great as I own several and all have some sort of quirk, as most predicta's are known for
Meanwhile back to the task at hand. What I have done is while monitoring the B+ with a DVM, (Pin 1 12CU5) I attached just the tuner B+ lead and watch the voltage drop as soon as the tubes warm up. I have looked for mechanical problems inside the tuner and don't really see anything obvious. I checked both tubes and they seem OK although I haven't subbed them as of yet. Gotta dig out my tube stash. So maybe something down stream connected to the tuner ?
Next I connect the brightness control by itself (Wiper lead disconnected from IF board) and again watch the voltage drop. What I don't grasp is how can a 100K control drop the B+ by itself. It seems to ohm out OK and I shot some deoxit also. It does vary the brightness on the CRT when it is connected so again I am a little puzzled.
On to the IF board when the 130 lead is connected the voltage drops. Measuring several points on tubes show low readings. Again the 255 is rock solid. I realize a number of components on the board could cause this but the brightness control just doesn't make sense to me especially with no load on it.
I'll move on to G1 and cathode next but for now work is calling. I'll dig out my tubes and look for a spare or order some.