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Originally Posted by Acesales1
Hello everybody- This my first post so I hope everything goes well. Thanks in avance for any help. I am working on a 1948 Teletone 7" electrostatic deflection set. I have completely recapped the set and brought it as far as you see in the photo. I have replaced a lot of resistors. I have checked all the tubes. As you can see it has a foldover problem. Can anyone give me advice on how to repair this? Thanks again! Alex
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Welcome! I hope you get the right tip to fix your set. Do you have a Sams schematic for it? If it is a TV149, it is SAMS 56, folder 22 dated 02/49.
Have you swapped the vertical output tube with the horizontal output tube [both are 12SN7s] to see if the problem moves from V to H? There are 4
12SN7s in the sweep section; swapping them around might pinpoint a weak one.
Might also be low B+. There is a selenium rectifier in the power supply that could be weak.
Use caution when you work on this set with it powered up; an isolation transformer would make it safer for you. There is no power transformer in the set to isolate the chassis and *one side of the AC line* is connected directly to chassis ground when the set is on. Also, be careful, there's 5000 volts on
the deflection plates of the 7JP4.
Best luck, it looks like it makes a bright picture.
Cliff