Quote:
Originally Posted by kbmuri
Hopefully the sound isn't making it out of the tuner, somehow. Next week maybe...
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To get a rough idea of where the bad part of the sound IF chain might be:
Do you get a fair amount of "FM hiss", like that you hear on an FM radio tuned between stations? If I recall correctly (IIRC) you were getting some detected audio, but very weak. If the sound IF is operational but on a wrong frequency, you would be able to get good sound but lously or no picture, or good video and no sound. Do you get much FM hiss with the TV tuned to an empty channel? If not, there may be a not working late sound IF stage that's losing you the sound signal strength. Or a weak link from the TV tuner to the sound IF, as you mentioned.
With your generator set to the proper sound IF frequency, do the alignment. But you should be able to set the output of the generator level to lower levels as you step thru the IF from the detector to the tuner. (you'd do this by injecting the generator output, via a small capacitor like 100pF @ 300V or higher rating, at various points (tube grids, tube plates) in the sound IF stages. You should be able to make it to the plate circuit of the tuner mixer tube (thru a capacitor) with a very low output setting on the generator. If you lose it, or have to jack up the level, you've found a problem area.