Quote:
Originally Posted by old_coot88
Sure, absolutely.
Well, when you hit G1 of the CRT (with the genny's output set high enough to see the signal), you should see whatever pattern the genny is set to. It might be negative though (that is, just like a photonegative). As you work back, you should see gain when you hit the grid of the video output stage (pin 7), and attenuating the genny as as needed, more gain at the grid of the 1st video stage (pin 2). This'll confirm that the video stages are working.
As mentioned before, since the detector diode is so easy to get to, i would leave it disconnected as a precaution against zapping it with the probe.
You'll probably see the pattern phase-invert (ie., shift from negative-to-positive) as you work back. That's because a tube's plate is 180 degrees out of phase from the grid. Grid goes positive, tube conducts more, pulling plate voltage down. Grid goes negative, tube conducts less, allowing plate voltage to rise.
oc
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When I inject video directly on pin two of the crt I am getting nothing more than the slightest change in raster. There is definitely not any sign of the pattern that the generator is outputting. There is control for phase +/-, adjusting this gives slight changes in the raster. When that control is left in the 12 oclock position there is no change in the raster from the generator in the off position.
I am using a piece of wire wrapped around pin 2 of the crt to attach my video output test lead to, and the negative test lead I'm attaching to the chassis.
I've also hooked up the generator to my living room tv's composite input and verified that the generator is in fact outputting a signal.
Is there some other way to verify that the crt is ok?
Could the signal be too high or low coming out of my generator to give a full picture when connected directly to pin 2 of the crt?
Will there be a party when this is all over that every one is invited to?
I can only answer the third one
.