Gottlieb Solved Joker Poker (Gottlieb, 1978) all CPU controlled solenoids activating at power-on

[JamesM]

I’m trying to solve a problem with a Gotlieb, System 1, “Joker Poker,” pinball machine.
Under normal circumstances, when the machine is powered on, the King Drop bank resets (it is controlled by a light diode that trips an under-playfield diode) and the playfield lights come on, and after 5 seconds or so the CPU cycles on and the displays alternate between zeros and high score, ready to play a game.
Currently, if the machine has been off more than a few minutes, when it is switched on all eight of the CPU controlled solenoids activate simultaneously and remain activated until the CPU cycles on after 5 seconds, after which the solenoids deactivate and normal operation resumes; oftentimes the 5amp slo-blow fuse for the 25-volt circuit blows.
When played, all features operate flawlessly.
The work-around I’ve been using is to turn the machine on and then turn it off immediately. Then I turn the machine back on and it functions properly without the solenoids activating.
Again, the game play is flawless; I don’t want to do anything that might jeopardize that.
Any ideas on a solution

 

[pinballdaveh]

I’m trying to solve a problem with a Gotlieb, System 1, “Joker Poker,” pinball machine.
Under normal circumstances, when the machine is powered on, the King Drop bank resets (it is controlled by a light diode that trips an under-playfield diode) and the playfield lights come on, and after 5 seconds or so the CPU cycles on and the displays alternate between zeros and high score, ready to play a game.
Currently, if the machine has been off more than a few minutes, when it is switched on all eight of the CPU controlled solenoids activate simultaneously and remain activated until the CPU cycles on after 5 seconds, after which the solenoids deactivate and normal operation resumes; oftentimes the 5amp slo-blow fuse for the 25-volt circuit blows.
When played, all features operate flawlessly.
The work-around I’ve been using is to turn the machine on and then turn it off immediately. Then I turn the machine back on and it functions properly without the solenoids activating.
Again, the game play is flawless; I don’t want to do anything that might jeopardize that.
Any ideas on a solution

Check the power supply output dc voltages.
Locked on coils usually means that the -12 volts is missing.

 

[JamesM]

Thanks, all of the power supply voltages are correct and all game-play features are functional.