Quote:
Originally Posted by bandersen
Well for starters you need to have around 6.3 VAC on pin 3 or the tubes not going to work properly. Pin #3 is going through a choke (L12) to the other tubes in the set. So I'd check that choke and also measure AC voltage in the heaters of other tubes in the set.
If they're all low, could be a problem with the power transformer. Or possibly something is shorted somewhere and really dragging down the filament supply.
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Yep, L12 is inside the tuner. 0.1 ohm fil. choke. Do you just check the resistance on it like a resistor? If it is bad, is it replaceable?
Testing pin three was very strange. With my multi-meter on the 20 VAC setting, I connected the ground wire to the chassis. Saw the meter register around 4 VAC. Then when I touched the other lead to pin 3 the volume on the set faded and then I saw smoke rising from a hole in chassis near where tuner is mounted. As soon as I removed the lead from pin three volume was restored. Reading was jumpy at best but did not get into double digits. I will test some of the other tube filaments to see that they are 6.3 vac.
The set has been on for periods of half an hour with a good raster and good volume. Just get zero TV signal across the dial and only get one radio station 91.9 fm across a good portion of the dial.