Low Voltage to Marquee Light

ScumBum

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I'm getting only 42 volts to the marquee light in my Galaga , how do I fix this ?
 
And you took this reading where?

The hot and neutral wires going to the light fixture .

When I got the game the marquee light wasn't working so I replaced the ballast , starter and bulb and it still gave no signs of life . I then replaced the two sockets at the far ends of the fixture that the bulb screws into and still nothing . So after all this I said screw it I'm getting a new fixture for $8.99 at the hardware store . I hooked it up and it still didn't work ! So I tested the two wires and I'm getting 42 volts . I'm not using the ground wire with the new fixture , cause its plastic and its plug doesn't have ground .
 
Chase the wires all the way back to the transformer and take the reading there at the trans. You may have a cold solder joint on the lugs at the trans.
 
Down in the bottom of the cabinet there is a half amp slo blo fuse for the power to the light fixture. Either the fuse is going bad (developing higher resistance) or the fuseholder is bad (tarnished or cracked fuse clips).
 
Thanks guys , I will check out those spots and report back .
 
Alright took readings at the Iso , the two top points read 59V and the bottom point read 120 .

The first fuse , 2 amp got 60V both sides

1/2 amp middle fuse was reading weird things like 24V and 1V on other end .

The last fuse on the right , I think 2 & a 1/2 amp read weird things also like 4V or 2V .

I thought maybe my meter was messed up getting those readings but every time I checked the Iso and the 2 amp fuse I got strong steady readings .

The game plays great though , everything else works just the marquee light has a problem .
 
Unplug the machine from the wall. Pull out the half amp fuse that runs the marquee. Now set your meter to the lowest resistance scale and measure the resistance of the fuse. Should be less than 1 ohm. Now while the fuse is out of the fuseholder, physically check the fuse clips for signs of tarnishing. Now squeeze the clips together a little closer so the clips grip the fuse better.
 
Unplug the machine from the wall. Pull out the half amp fuse that runs the marquee. Now set your meter to the lowest resistance scale and measure the resistance of the fuse. Should be less than 1 ohm. Now while the fuse is out of the fuseholder, physically check the fuse clips for signs of tarnishing. Now squeeze the clips together a little closer so the clips grip the fuse better.

Ok thanks , the fuse is brand new , I replaced all of them in the game . The fuse clips from what I could see , it was pretty dark , they looked tarnished and rusty . Whats the best way of cleaning them ?
 
These fuseholders are known to go bad. Midway used some really crappy fuseholders. I would replace the fuseholder with a new one.

However, if you want to clean them, you could use a Dremel tool with wire wheel to buff the clips clean. Some people have used "C-L-R" (Calcium-Lime-Rust remover) from the grocery store to clean the metal. Just dip a cotton swab in the C-L-R and wipe the clips with it. Should eat the tarnish right off. Follow with cleaning off the clips with a cotton swab dipped in clear water. Now dry the clips off with either a rag, dry cotton swab, or a hair dryer.
 
Ok thanks , the fuse is brand new , I replaced all of them in the game . The fuse clips from what I could see , it was pretty dark , they looked tarnished and rusty . Whats the best way of cleaning them ?

Just because the fuse was new....doesn't mean it still couldn't of blown....after all, power has been applied.
Edward
 
And just because , because , because you might because and then you'd be screwed because .....

Haha just kidding guys , thanks for the help !

What sucks is I just placed an ordered with Bob Roberts , which arrives today and I could have gotten a new fuse holder .Shoot ! I guess I'll try cleaning it and see what happens .

Thanks for helping me locate the source of the problem .
 
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