19k7000 wave on top on image

Jaydon

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Donor 2020-2021
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I've been scratching my head on this for a while and figured it's time to see if someone has any ideas. There is wave, or rather a shift, on the top of the screen.

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I thought maybe it was something with the TPG, so I hooked the monitor to a game. The artifact is still there.

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When in grid pattern on the TPG, the vertical lines are wavy.

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I can minimize this wave if I turn down the contrast. But it doesn't completely go away.

Here are the details:

This is a 19k7000 P447d chassis married (or rather first date) to a TV tube https://tubular.atomized.org/tube/A48AFN22X

The chassis has had a full recap kit (with a new filter cap), reflowed, and has the original flyback.

The tube has clean guns, Vertical Ohm 13.0, Vertical Inductance 27.3mH, Horizontal 4.8 Ohm, Horizontal Inductance 3.2mH

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I read that this might be a grounding problem. I have 128 Ohm between the aquadag and the dag wire. The dag wire is wrapped around the monitor frame and is hooked up to the neck board. The neck board is also grounded to the chassis frame. There is continuity from the dag wire to the neck board. The monitor frame is also connected to the grounding strap inside my Joust cabinet. Again, there is continuity between the monitor frame and the grounding strap.

Another possible cause I read about is a sync issue. I have the the TPG hooked up to separated vertical and horizonal syncs.
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The game in the picture above was hooked up using composite sync on Pin 10 of the chassis.

If anyone has any ideas, I'd love to hear them.
Thanks.
 
unable to adjust out with the right combination of horizontal position and h-freq / hold?
 
unable to adjust out with the right combination of horizontal position and h-freq / hold?
I can just about get rid of it in one test screen by adjusting the h-freq and h-position.

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But when I switch screens on the TPG, it is still there.

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Also, I forgot to mention this earlier. The B+ is measuring at 123.5 Vdc
 
your IC2 may be going bad, LA7823
Sorry for the delay in responding. I had to order some LA7823's from APAR.

I did replace IC2. And with the contrast all the way down, I can almost get rid of the wave on some of the test screens.

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I noticed some linearity problems at the bottom that can't be adjusted out using the frequency pot. I'm thinking this is a compatibility issue between the chassis and the TV yoke. I have another k7000 chassis coming in tomorrow. I'm going to swap out this chassis with the new one and see if there any differences. I'll report back.

Thanks again.
 
I tried 2 more K7000 chassis on this tube. Both with the same results.

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Looks like it is a Yoke issue. Which really sucks since I have 5 of these TV's in my garage. Time to start collecting yokes for a complete tube swap.
I'm going to try it with a couple of other games and see how noticeable it is. I'm also going to try one of the other TV's. Maybe it's just this one that is messed up.

Does anyone have any other suggestions?

Hey @bigrussel . You were looking for a tube. Do you want to take a chance on this? If so, it's yours. Send me a message.
 
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