Problems with K4900 monitor

GTBoom

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So I may give too much detail but I am trying to provide any information that may get me closer to a solution.

I purchased Ninja Gaiden in a Williams Cabinet with the sides painted black. Owner said it was originally moon patrol but I am thinking it was a Joust. The game worked when I bought it but the picture was very dim. I loaded it in the back of my truck. It was laying on its back with the monitor up. I got home late and was tired so I left it there until the next morning. I woke up early to unload it and I found that it was lightly sprinkling outside, almost misting. I quickly unloaded it and got it under the garage. I wiped it off, plugged it in to play a few games before I was off to work. Probably a dumb idea. I heard a few pops and a sizzle noise. I quickly turned it off. I decided to let it dry out. Later that night, I turned it back on and saw a little neck glow. After about 5-10 seconds, it slowly faded and went out. I flipped the switch off and back on. Nothing happened other than playing blind.

I decided to swap in another K4900 chassis. I did not change the yoke or neck board. The same thing happened. It turned on, got a little neck glow, and went away after 5-10 seconds. I flipped the switch off and back on. Not getting anything now.

I am still new to arcade repair so any insight on how to fix this would be great. Should I switch the yoke and neck board now or is there something else causing the problem?
 
my bet is that there is some moisture in the anode hole.

or you could have cold solder joints or cracked traces on both chassis.

have they been rebuilt with new caps and had a good re-flow done to them.

and did you hook up the dag wire to both chassis.

Peace
Buffett
 
Most likely, you have a power problem in the cabinet. Pull the monitor and either test it on the bench or in another cab.
 
I don't think its moisture. I let it sit for 2 weeks before I swapped the other chassis into the cabinet. I will look at the joints and traces. Neither have been recapped. What is "dag wire"?

Power problem... I will swap the monitor into another cabinet and see what happens.

Thanks for the suggestions as I am still learning.
 
some pictures....
 

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some pictures....

Picture #2 shows me that you most definitely have a power problem in the cabinet. It is a pretty common problem for Williams boardsets and usually doesn't affect the monitor. Your boardset may be shutting down on you from what I see.

Test the monitor in another cab or on the bench or hook a sig gen up to it. I do not think that you are actually having a monitor issue.
 
the dag wire is the black wire on your tube that connects to the neck board.

it is on the left side of the tube in your game.

it looks to have had a cap kit but may not have had a reflow done.
you won't know that till you take the chassis out.

i can tell the neck has not been reflowed due to it still having the original ties holding the cardboard on it. but cannot tell if the chassis has had it done or not.
can't see the bottom of it.

Peace
Buffett
 
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