I just replaced all 3 flipper coils on my No Good Gofers. When I go into flippper coil test mode, all 3 flippers fire correctly but the hold test has me wondering something. The lower flippers make a faint noise but don't fire when in hold test. However, the upper flipper fires and holds when in hold test. It also buzzes a bit. Is this normal? The game plays fine but I don't want to ruin something if the hold isn't working correctly.

I noticed that each new coil has 2 diodes on them. The old coils are a different story. One has both diodes cut, one has both diods intact and the other has only one diode.

Can anyone shed some light on this?

Ahhhhh, that makes sense. I held the lower flippers and started the hold test. They stayed up. Thanks!

Well, there's still a problem. While playing a game just now, I had the ball trapped on the lower right flipper and the upper right flipper died. It was making a buzzing sound like I said in my original post, then it just died. Fuse F118 is blown.

Any ideas??

I just replaced the fuse and put the original coil back in. The upper flipper works again but is still buzzing when I hold it. I also watched the fuse while holding the flipper and the wire inside the fuse moves so it's under more stress than it should be. It's a 4 amp like the manual calls for.

Now, when i rebuilt the flipper a couple nights ago I accidentally reversed the red and orange wires. I know....stupid mistake, it was super late and I was tired. The game froze up the first time I hit the right flipper button and I immediately turned the game off. Would the reversing of those two wires have caused any damage to the board somehow? And what damage would that be?

Here's a pic of my coil and wires.

IMG_1068 (resized).JPG

Well after troubleshooting this some more, I ended up snagging a known good coil out of another game. The flipper works correctly now with no buzzing. Apparently when I reversed those two wires I fried the coil. DOH!! Time to order another coil. Thanks for the help guys.

The game is new to me and the coils looked pretty old. I like to know my flippers are fresh when I buy a used game and don't know the history on it. Peace of mind I suppose....