Hello Pinside! This is my first System 1 machine. I just got it. Game boots and plays well for a while and then it appears that the Q relay loses strength and all playfield coils lose power. If I physically move the relay they regain their power. Testing across the coil lugs when activated reads 25 volts. When it loses strength that reads like 5 volt for so. Voltages on the power supply seem to remain fine.

Game has a NiWumph MPU, Rottendog driver and a Gulf Pinball power supply. There appear fairly new and unhacked.

What could be causing this type of behavior?

OK, so I have been messing with this for a minute now. here is an update on the situation. I noticed that when measuring voltage across the coil lugs at the Q relay I get 25 volts and then the more switches/solenoids I trigger is when the voltage might start dropping. If I measure just the + lug on the coil and a remote ground location I get solid 25 volts. Across the lugs is where there is a problem. Also I get a consistent 4-5 volt drop when I trigger a 10 point switch and the "5000 when lit" light is lit near the top kick out hole. Interesting.

This led me to follow the negative wire from the Q relay up to the solenoid driver board (Rottendog). everything seems fine there, but I notice that there is an LED that should be lit when the board has 5 volts. It is not lit. I measure for 5V coming from the MPU at the connector to the Solenoid board (A1J5 #23 Red wire) and only get 2 volts!

If I unplug the solenoid board and measure the same connector I get 5 volts.

I unplugged all connectors to the driver board. I connect the MPU and the voltage measured at the driver board instantly drops to around 2 volts.

Any ideas?

I have a bunch of supplies coming to redo the connectors, but I think that there is an issue with the Driver board as the voltage drops immediately when I plug the connector into the board and angle it so the 5 volts is the first to make contact. Seems like the connectors are not the issue.

What do you think?

bump?

Weekend Bump?! I acquired a Ni-Wumpf driver board to eliminate any Rottendog/Ni-Wumpf incompatibility.

If I unplug all connectors besides the power supply from the MPU and Driver Board I have 5 volts at A1J5 #23. As soon as that connector makes contact with the driver board the voltage drops on that connector to less than 1 volt. If anything the Ni-Wumf driver board makes the game work less.

I emailed Ni-Wumpf, but it is the weekend so they didn't get back to me.

Anyone know what is up with this?

Thanks! I was feeling all alone!

I am pretty sure it has to be the MPU , because the problem exists with pretty much all connectors unplugged. I hope Ni-Wumpf gets back to me.

Problem Solved.

I guess when you get a Gottlieb System 1 you should repin the connectors like literally everyone says. I repined the connector and there is strong DC power to the solenoid board and everything is right with the world.

I was confused by my reading of low voltage at the same spot that I previously had good voltage. I guess my electrical theory needs work.

I think that the fact that the game initially worked for a while and gave me such interesting symptoms put me in the weeds for figuring this out. I should have started at step 1.

Thanks for the correct diagnosis CactusJack! Thanks for letting me know you were reading BorgDog!

Also, Ni-Wumf totally contacted me back and had a similar diagnosis. You don't hear too much about Ni-Wumpf on Pinside, but they legitimately were trying to help me out they deserve recognition for that.

Now I have to knock down some drop targets!