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  #1  
Old 10-24-2008, 06:46 PM
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Tube Radio Tube Radio is offline
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You should run the filament of that rare CRT on a 6.3 volt transformer and sub a resistor in the heater chain in place of the CRT filament as I've read somewhere many of those tubes failed due to bad filaments caused by the surge in voltage when the TV is first turned on which is why they are so rare today.
Here's a link to one someone restored. http://www.electronixandmore.com/tel...lot/index.html
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Old 10-25-2008, 03:16 PM
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Phil Nelson Phil Nelson is offline
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Quote:
Originally Posted by Tube Radio View Post
You should run the filament of that rare CRT on a 6.3 volt transformer
Yes, I bought a small filament transformer that should fit neatly in back of the HV cage. Meanwhile, I just bring it up on a variac when I want to test it.

The HV still seems low. The picture is only viewable in a dark room, and twiddling the trimmer inside the HV cage doesn't help. I'm not quite sure where to go next. There are a couple of multi-meg resistors that I haven't replaced yet. Also a pair of 300mmf/3kv mica caps that lead to deflection plates. Time for another parts order, perhaps.

On the upper channel range, the picture is clear and stable, and the audio is excellent. Nothing but feeble audio on the lower range, but I'm not going to worry about that until I get the power supply sorted out.

How critical is the position of the little metal collar on the 1B3GT tube? I marked the tube with a Sharpie when I removed the tube for testing, and I believe I got the collar back where it was before. Of course, the TV wasn't working at the time, so who knows if the previous owner may have shifted it around.

Phil
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