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Old 09-27-2013, 02:54 PM
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TinCanAlley TinCanAlley is offline
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Join Date: Sep 2008
Location: So Cal, CA
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Quote:
Originally Posted by andy View Post
Have you tried scoping the CRT cathodes to see if the ringing is there? This will tell you if the problem is getting in through the video chain.

I would also try placing the scope probe tip near (NOT TOUCHING) the case of the HOT to see if there is any ringing on the signal you will pick up. Try the same thing near the yoke, and yoke wires. You will need to use a low volts/div setting, but you should be able to pick up radiation of the horizontal sweep signals. Don't try to measure them directly since the high voltages pulses will damage the probe, or scope.

Your problem could be caused by the flyback, or yoke oscillating. This seems likely to me since the bars are clearly synchronized to the horizontal sweep, and you seem to be seeing it everywhere that has pulses from the flyback.

Finally, can you remember if it had the problem when you first got it (before you did anything to it). I seem to remember that you didn't mention it until you had done a lot of cap replacement.
The problem was there before the recap. I didn't mention it because I figured it might have been a bad cap. That and whoever worked on it before messed up just about everything (pincushion, convergence, greyscale, etc.). It looked like crap, yet the person selling said it worked and looked great. It really wasn't until I started cleaning it up that I realized how bad the bar actually were.

I will put on the safety cover on the probe and let the plastic rest on the HOT to see if I can get a signal. I'll do the same for yoke and yoke wires.

Now the base of the HOT get the horizontal pulse from the horizontal board. I checked all those points on the horizontal board and they matched the waveforms given. The HOT's signal on the base has to go through the horizontal transformer. I haven't scoped the base of the HOT, so maybe that should be next. Maybe there's a problem with the transformer. The SM does show a waveform for the base of the HOT. It says it should be 7V.
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