Wells 4915 no green....

descrentl

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So, after finally getting my Paperboy running correctly, we realized I have no green. Can someone school me what usually goes bad when you lose a color? Ive heard of rejuving to get colors back, but I want to know what normally fails when you lose a color. Ive reflowed all the joints on the neckboard and chassis, with no change. What else should I be checking for?
 
Had a similar problem when I noticed I had no red color.

First I'd determine if it was the monitor itself or the PCB. To check if it is the PCB, I'd try swapping the video output pins on the PCB (swap the green with red and see if it persists).

I'd bet the monitor though. If you've reflowed everything on the neckboard, I'd then try swapping the color transistors on the neckboard (again green with another color). Then I'd try maybe swapping the cutoff & gain pots.

I'm already guessing you did a capkit.

The final thing that got my red working again was a blast on the rejuvenator.
 
there are two color transistors on the main board and one on the neck board. swap them out one at a time and test, that will atleast eliminate them as being bad.
 
Just to bump this, I swapped pins on the red blue green white connector around, and I still dont get any green. I also noticed I have no yellows as well. Are the colors I see in MAME the same as they would be on my upright? Where greens are supposed to be, I get blacks it seems. Swapping the pins puts whatever color I swapped with there ie, if I swapped the green and red pin, I now have reds where Im supposed to have greens. So is that telling me its the green drive on the neckboard? Also, not having yellows, is this a direct result of having no green?
 
If I am understanding your post correctly, the game board is generating a proper green signal so it's either the neckboard or the gun itself.

From here, I would desolder the signal at the neck socket (usually a resistor there, lift a leg) and use jumpers to swap colors there. If red (or blue) signal activates the green gun properly, it's the board. If a good signal does nothing, it's the gun.

If it's the neckboard, swap color drive transistors (then pots) around and look for a change.

There are only three primary colors (RGB) in a crt, so forget yellow until RGB are fixed. Speaking of which, there is no yellow in a color gradient pattern. Start using a test pattern instead of a game and it will be faster/easier.
 
If I am understanding your post correctly, the game board is generating a proper green signal so it's either the neckboard or the gun itself.

From here, I would desolder the signal at the neck socket (usually a resistor there, lift a leg) and use jumpers to swap colors there. If red (or blue) signal activates the green gun properly, it's the board. If a good signal does nothing, it's the gun.

If it's the neckboard, swap color drive transistors (then pots) around and look for a change.

There are only three primary colors (RGB) in a crt, so forget yellow until RGB are fixed. Speaking of which, there is no yellow in a color gradient pattern. Start using a test pattern instead of a game and it will be faster/easier.

Thanks, will try this now.
 
Ok, I tried resistors and no change. While I was trying to swap pots, I broke a leg off of the red pot. So the one that was in green, is now in red and works fine. So now I need a pot. Anyone know what kind of pot and value this is so I can get another?

EDIT, I got it from the manual. Nothing like a nice setback when troubleshooting.
 
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You said you you "tried" the resistors. Did you just swap them around, or did you lift one leg of each and swap signals around with a jumper wire. If the former, all you determined is that it wasn't a bad resistor. If the latter, it's your green gun.
 
Well I took the chassis to another KLOVers house. The chassis works fine in his Toobin. So it may be the tube, or the Paperboy board. But I can rule out the chassis.
 
So, for anyone who cares, it turned out to be a bad tube. We rejuved the tube and now its good to go. Ive never seen a color completely go out on a monitor before, but a few shots of the rejuve cleaned it up. Big thanks to KLOVers Robran68 and joeyoravec for the support and rejuve.
 
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