The 100 meg resistors only made the situation worse (as expected), there was even less convergence voltage available. Ohm's Law wins again. Then I tried a 25 meg resistor as the first one coming off the ultor going to the DC conv. pot, and bingo it popped right in! Unfortunately dropping so much voltage is causing it to heat up in a hurry, so voltage drops as time goes on. I've decided to order five 5 meg resistors at 2 watts a piece, which will give 10 watts total dissipation. This will spread the voltage out over more resistors (and thus more surface area), and hopefully cure the drifting issue. Once I am able to keep the convergence voltage stable, I will finally be able to post properly converged pictures of the proto tube. Here's where I'm at right now.
As you can see, blue is still slightly high and red is a little displaced as well. These are static convergence issues, which are easily cured by twiddling the magnets on the neck of the tube. Ignore the faint blue bar at the far right, I think the tuner is receiving interference from the stray static field escaping the CRT. I will need to construct a supplementary shield, to make sure all the ultor potential remains trapped. Heavy plastic should work. Yay progress!
06-14-2012, 09:17 PM
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