You're flying too low!

[leadlike]

When I recently installed my 21cbp4 to replace a 21amp4a in my RCA set, I found it to be a pretty effortless job. What with pulling all of the magnetic focusing stuff out of the set, it was very nice to just drop in the chassis, plug in the yoke, and have a nice, centered picture. Or so I thought.

Because now after a few hours of watching, I noticed that the vertical is deflecting downward a bit too much. I have to ramp up the vertical height all of the way to fill the screen. This increases the vertical oscillator's plate voltage from the optimal 160 volts to 230 volts. I realized that the Olympic set the 21cbp4 came from had some centering magnet tabs on the yoke, while it has none in this set. Since the yoke cases were of the same construction, I was able to simple remove the back end of the Olympic yoke (with the centering magnets) and place it on the RCA's yoke.

While this looked neat, I was disappointed to find that the screen was reduced to a tunnel vision effect, pretty much how it would look if I had racked the yoke back about three inches. Can anyone explain what is happening here? Is the RCA's sweep circuitry causing this, or is this yoke just not built to take centering magnets? If it is the latter, it looks like I can put the Olympic's yoke in, so I may finally have a centered picture, but I don't want to fry anything by just blasting ahead.