Hello all,
My first post here, and I'd first like to thank you all for the great tech info here. Much appreciated!
I have a Space Station that had quite a few problems in the past apparently.. someone has installed a Rottendog MPU004-1.
The toughest problem when I got the machine, was on boot up, it would blow F3 regularly- not always, but one in 3 times approx.
I eventually found that the blanking signal for the solenoids was shorted to ground by the top center board mounting screw. When the game would boot up, the solenoids would fire. There's a trace that runs right next to that screw and it's shorted soon as you put the screw in! Left the screw out to fix that.
Now, the game plays great except that every once in a while- F3 (2.0A SB) blows during game play. Special solenoids (jet bumpers) stop working.
I've checked the leaf switches and alignments for the jet bumpers, best of my ability.
Has anyone run into this?
A 2.5A fuse will blow just as easily.
I've checked the harness (red/wt wire) its full length, don't see anything.
One thing I'm not sure of, is sometimes, very intermittently I do hear a few solenoids fire on bootup, but not hold on.
Any insight would be so appreciated!!

Thanks,
Don

Yes it is the original supply. There is some hum in the audio. Has it been known to cause solenoids to fire on bootup from some AC ripple?
thanks for the suggestion.
D

Found the problem finally.
One of the jet bumpers' plastic body was cracked and it would intermittently allow the plunger to come down on enough of an angle to depress the skirt (switch), which of course would keep that solenoid energized. Found it by putting my ammeter in place of F3 and taping it to the front of the machine, and playing the game till I saw it show me 5A draw. Quickly looked at which jet bumper was down and now I know.