Quote:
Originally Posted by Penthode
On the older KRK2 tuner used in this set, there is a screw for each channel. But before you touch those, it is worthwhile to swap 6J6 tubes around. The inter-electrode capacitance difference between tubes may be sufficient to bring the tuning within range of the audio. Try exchanging the oscillator with the two othe 6J6s to check that out.
You do not have to worry about the front end RF tuning because the tuning is very broad. The oscillator is the critical one and you have to be within a few hundred kHz to hear anything.
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Couldn't one hook his digital to analog converter box set to Ch 3 or 4 rf carrier(no antenna) to the set's ant input and monitor the DC voltage at the output(pin 1) of 6AL5(V116) sound discriminator? With the TV's ch selector set to the corresponding carrier frequency it seems pin 1 should be at or very near 0v DC when everything is aligned correctly. If this works I'd set the fine tuning to center and adjust the Ch 3 or 4 oscillator slug in attempt to read 0 DC volts at pin 1. This assuming the sound IF and discriminator adjustments are very near their previous tampered with settings.
08-25-2022, 02:58 PM
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