27-inch medium res monitor color question

bones3010

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The red color in the monitor in my Gauntlet Legends cabinet is starting to fritz out... If you whack the side of the machine occasionally it will come back on but will crap out again soon thereafter. It's a Zenith model. Can anyone think of what could be causing this and what I should/could replace to fix it?

Thanks! Monitors are my weakest area in this hobby!
 
if it's the original monitor with the cabinet it's probably a Wells-Gardner K7500. I've seen this particular symptom on several U5000s and K7500s, it's just a bad design on the neckboard where the color drive transistors get very hot and it leads to cold solder or even worse yet, lifting traces.

so that will cause your smacking the cabinet to bring colors back.

ordinarily what I would do is DESOLDER the transistors completely out, clean all the solder pads up, then reinstall them. if you have lifted traces, then that's where it gets complicated. I've taken brand new transistors and without cutting the legs off them, folded them onto scraped traces (so you can apply solder to them) and make it work that way. the folding onto the trace will additionally hold it down so it won't move.

you might have to send it out for repair or find someone local to you that can do such a thing.

even if it's not a K7500 and it's the Neotec uh, maybe 25E or 2501, the same fix applies. color drives just get hot and the solder joints break down. just hitting them with fresh re-melted solder can usually take care of it.
 
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if it's the original monitor with the cabinet it's probably a Wells-Gardner K7500. I've seen this particular symptom on several U5000s and K7500s, it's just a bad design on the neckboard where the color drive transistors get very hot and it leads to cold solder or even worse yet, lifting traces.

so that will cause your smacking the cabinet to bring colors back.

ordinarily what I would do is DESOLDER the transistors completely out, clean all the solder pads up, then reinstall them. if you have lifted traces, then that's where it gets complicated. I've taken brand new transistors and without cutting the legs off them, folded them onto scraped traces (so you can apply solder to them) and make it work that way. the folding onto the trace will additionally hold it down so it won't move.

you might have to send it out for repair or find someone local to you that can do such a thing.

even if it's not a K7500 and it's the Neotec uh, maybe 25E or 2501, the same fix applies. color drives just get hot and the solder joints break down. just hitting them with fresh re-melted solder can usually take care of it.

Just wanted to send a delayed thanks! ;-)

FYI, it must not be an original monitor, because it clearly has a "Zenith" label on it... Not sure what particular model it is though.

Curiously, I was having a different issue with the game resetting that appears to have been cause by the power switcher sending too-low current (4.7 volts to the boards). I upped the power and the resetting problem seems to be gone for the moment. Also, I haven't noticed the red flickering like before. It may be coincidence, but could that low current have been causing the color to get funky like that?
 
Just wanted to send a delayed thanks! ;-)

FYI, it must not be an original monitor, because it clearly has a "Zenith" label on it... Not sure what particular model it is though.

Curiously, I was having a different issue with the game resetting that appears to have been cause by the power switcher sending too-low current (4.7 volts to the boards). I upped the power and the resetting problem seems to be gone for the moment. Also, I haven't noticed the red flickering like before. It may be coincidence, but could that low current have been causing the color to get funky like that?

Zenith is just the tube. the chassis that plugs into it, that's what's different. as I said before, the K7500 came with Zenith tubes, I don't recall if Neotecs did too... I was just trying to narrow down what you might have cause that's what they were shipping with back then.

Zenith did make a monitor, the K7000A, but that's standard resolution, and I seriously doubt that's what you have.

the power supply that operates the game board is completely independent from the monitor's functionality, so unless you do in fact have a board issue causing your red problems, the power supply voltage setting has nothing to do with what's going on with the monitor.
 
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