Issue with GE "Portacolor III"

[kf4rca]

Do you know for sure that the tuner is working?

[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.

[Jeff]

Having thought about it, I took the output of the broken set's tuner (hooked up to dvd player) and jumpered it to the working set's tuner input, and the signal doesn't look half bad, a little lossy, but alligator clip leads across the bench don't help, so.... I think the tuner works.

[dieseljeep]

Originally Posted by Jeff

Having thought about it, I took the output of the broken set's tuner (hooked up to dvd player) and jumpered it to the working set's tuner input, and the signal doesn't look half bad, a little lossy, but alligator clip leads across the bench don't help, so.... I think the tuner works.

I'm almost positive I have one of those sets in my cluttered warehouse.
If it's easy to get to without help, I'll check it out and PM you in a few days.
I'm glad I quit the repair business 30 or so years ago. I don't miss those headaches.

[Jeff]

Originally Posted by dieseljeep

I'm almost positive I have one of those sets in my cluttered warehouse.
If it's easy to get to without help, I'll check it out and PM you in a few days.
I'm glad I quit the repair business 30 or so years ago. I don't miss those headaches.

Thanks! Whether you find it or not I appreciate the gesture

[zeno]

OK first give a detailed description of the symptoms, I think I am
missing something here. Do you have a color picture that goes away to blank white when the color control is turned all the way down ?

AGC When there is no signal or very weak signal both the RF & IF are turned on to full gain. With strong signals gain gets turned down. SO AGC voltages
can vary a lot. Most SS sets the AGC control will go from snow to normal
to a jittery pix as you turn it. Set it to where the snow just goes away..

TUNER Most tuner fails are snowy pix or whited out & wormy. Crude test
is turn the channel. You should see "noise" in the pix & crashing in the
sound. If you do the problem is tuner related. If not its IF related.
Keep in mind sometimes tuners get so dirty they stop working unless you violently shake the knob !

73 Zeno
LFOD !

[dieseljeep]

Originally Posted by Jeff

Thanks! Whether you find it or not I appreciate the gesture

I located it today. I ran it for a few hours. I probably haven't turned it on in several years. When I first tried it back then, I remembered the CRT was a bit tired on the red and blue gun, but after a minute or so, the grey scale doesn't look too bad.
It's a model # 10AB3046W in decent cosmetic shape.
PM me with your phone number, as I'm not that fast on a keyboarder. Phoning is easier. Dave.

[dieseljeep]

Originally Posted by Jeff

Thanks! Whether you find it or not I appreciate the gesture

I still have to get my paypal straightened out.
Evidently you don't need the set anymore. That's alright with me.