Old Monitor Bad Tube, Replaced with Sampo KGR-1901H with Scrolling Issue

arcadegarage

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Right now I have a tube in my Bud Tapper with no Green and can't be rejuvenated. Has a recapped WG 19K4906 chassis. Before swapping chassis I thought I would try a spare monitor I have lying around.

I installed a Sampo KGR-1901H monitor today. It worked but the picture scrolled bottom to top. I don't think it was the pot, it just wouldn't click into place and grab a hold if you know what I mean. Adjusted the B+ and it didn't help.

Then we recapped the Sampo chassis, including the 2 big filter caps, and adjusted the B+ to 110.5V.

Picture still rolls. What could it be?

If we can't fix it, then we may have to swap the good tube with the WG chassis as a backup option. Are they compatible?
 

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here's the manual: https://www.arcade-museum.com/manuals-monitors/Sampo_19in_Color_Monitor.pdf

page 12 shows the board layout. the plug with the black, white, and brown/orange wires is on the negative sync header.

if you go to page 6 that lists the pinout, and L header pin 1 is ground, pin 2 is negative vertical sync, and pin 3 is negative horizontal sync. if your black wire is in fact video ground, then that plug is on backwards. also you have the plug off a pin, and it definitely looks like it's plugged in backwards. it could be that simple. lol
 
Thanks for all the help so far. Here's an update.

When we took the neck board off, the 7 pin was bent and wasn't getting connection to the neck board. Guess what, the 7 pin affects the green. We tested it again after fixing the pin, and the green was better, more on the yellow side, but better. The red now was a problem. Being that it had some pretty bad burn on it, and the fact that I'd rather have a Wells than a Sampo, I swapped the tube anyway and am going to keep the old as a spare.

When putting the new monitor in the game after the tube swap, the degaussing was really off along with the convergence. We spent some time fiddling with the rings and got the convergence right. Moved the yolk up and down the neck, but the degaussing still had issues.

We broke out the corded drill and degaussed it ourselves. Note, the AC from the drill works 100 times better than just a magnet. Seemed to mostly do the trick. Next week, we are going to swap out the degaussing coil from the other tube for good practice, and to see if that helps with the degaussing further.

Overall, it was a successful tube swap with some lessons learned about double checking the neck board pins, how much the yoke and rings need to be placed correctly on the neck, and to consider using the degaussing coil that's mated to the chassis vs the tube.

Picture is nice and crisp, and without burn. Tapper is almost ready to go out on the floor! Thanks!
 
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