jones plugs, with game on move the plugs out and in a tad

Do the coin chute lights behave the same way? If so it could be that the fuse or fuse holder between black-red and white wires.

/Mark

Id remove all of the bulbs in the head and start putting them back in one by one in until you get to the one that blows the fuse. It could be a bad socket or something touching a socket or socket wire causing the short.

Good luck..its a great game with interesting rules including the potential 4x inball bonus on the last ball..big risk-big reward on that shot.

I don't think that removing all the bulbs proves anything. You could try removing the jones plugs for the backbox and coin door to see if that fixes the problem. Then plug them in one at a time to see which one blows the fuse. That might narrow down the problem. Other than that you need to examine every socket and ground wire to see if it's touching anything it shouldn't.

I'd suggest disconnecting the power while removing or replacing the jones plugs.

I agree that's where I would be looking since you replaced the bulbs.
20220518_104257 (resized).jpg
Great game just finished rebuilding a pioneer.
Raff

If you took all of the bulbs out of the circuit, take one of your blown fuses and solder a bulb onto that fuse. Then put it in the fuse holder. That way you can begin to troubleshoot where the short is visually as the bulb will be lit with a short down the line.

Look for a wire that maybe touching a higher voltage circuit.

Check the Jones Plugs and the ground braid.

Check to see if any of the bulbs sockets are being touched by another wire or grounding against something in the back box.

You might also test in the dark and look for a spark/arc to identify the location of the short. This might take 2 people if the fuse blows quickly. You might even jump the fuse for a few seconds and quickly check the back box.

I surmise when you put a bulb back in the center spring loaded tab of a bulb holder turned and is now touching the wire to the outer portion of the holder. With all bulbs out of that circuit, using a bulb in the fuse holder acts as a current limiter so no wiring or transformer will be harmed as it's drawing so little current. It also acts now as an indicator. If there's a short, it will light up. If you feel that the problem is in the backbox as you mentioned that this problem cropped up after changing bulbs, I'd attach long enough wires to bring the indicator bulb back there. Then with jones plugs in and machine turned on I'd start monkeying with each socket. If the light goes out, that's where your short was.
However, if you left any bulbs in that circuit and you find the short, the indicator bulb will now dim rather than go out.

If you could post a picture of the globe with a fuse
Soldered on that would be good .
Raff

Heat shrink over blown fuse to keep ends from separating from glass, you could use a socket for the globe but did I have any? Noooooooo

Current limiter 6 v (resized).JPG

Any chance of showing the fuse without the heat shrink I know it's asking a bit too much .Just want to see how it's soldered on.
Raff

A lead to each end, no short across the fuse.

Thanks man
Raff

One way to help isolate where the short might be would be to block switches that drive groups of bulbs in the back box.
Pioneer backbox short switches (resized).jpg
For example blocking the BX switch above would remove all of the Match lights and AS relay wiper disc from the GI circuit. Blocking the AX switch to the left of it blocks even more lights. Blocking both sides of the P2C make/break switch would remove the player up lights. You'll find more on the schematic.

If you block a switch and suddenly the fuse doesn't blow, or the bulb replacement fuse doesn't glow, you know that the short is in the circuit cut off by the blocked switch.

And... inquiring minds wanna know what the issue was?