Ok. Let’s try this again…RCA 9TC240 Alignment

[Penthode]

Originally Posted by Chris K

I guess I don’t know what detune means. What am I looking for on the cram when the signal is injected as stated and I’m looking at DC voltage on the meter? Or am I just way off base?

Yes you are looking for a maximum dc. The CW signal is just an unmodulated sinusoidal signal. The discriminator is rectifying it hence dc on the vtvm. It could be a positive maximum or negative maximum with respect to ground. So long as it is maximum.

The s curve will be a positive and negative wrt ground. It will be linear between the two peaks. That is because the discriminator is a frequency to voltage converter.

Yours is a split sound receiver. You must be aware of that because it tunes differently from a later intercarrier sets. When you adjust the fine tuning control, you tune for best sound. You will fine tune the FM sound signal across the s response: as you approach the correct tuning point, the sound will become stronger as you approach the slope of the S, next you will then hit total distortion at the peak or null of the S and then clearest sound when the fm signal is swinging between both peaks. If you tune further you will hit distortion again. So the proper point is between the two distortion points. When the set is properly aligned, the picture should be optimum when you tune for best sound.

Consider what I have said above. If it isn't clear you must question before proceeding with the alignment.