Issue with GE "Portacolor III"

[Jeff]

Originally Posted by kf4rca

Do you know for sure that the tuner is working?

Actually, no. I don't really know how to "test" the output of a tuner, I know it takes RF and turns it into IF, but I don't know how "check" for IF, (I don't have a sweep generator, or a "tuner subber") But I guess that's what "snow" actually is, the output of a tuner without a signal. Maybe the tuner isn't putting out the IF it should be, and so the IF amp chip has nothing to modulate? That being said, I took the IF output from the tuner of a working set that I have and jumpered it to the tuner input of this set, and there's still no video signal. Although, I'm not sure if you can just use another tv as a "tuner subber", as I just used the output and ground of the other tv's tuner.