I bought my first pin a few months back - a STTNG - and an unexpected surprise to the game was the secret mode where you get to play as the ship's Chief Engineer, Geordi LaForge, and try to fix the darn thing every week! You know the designers were a fan of the show!

After spending much time last week finally tracking down a bad opto and replacing it, rebuilding all three flippers and fixing the drop target in back, this thing was playing beautifully for about 3-4 days. Then on Saturday night, after playing about a dozen games or so I leave the machine on (attract mode) to take my cat for a walk (a different story) with the intention of playing more when I returned. About 30 minutes later, upon my arrival I find that all the playfield boards have lost power. Everything else is powered (lamps, switches, DMD) but not the opto boards or gun motors.

The 16 Opto board and trough boards are both powered by +12V delivered by J118 on the Power Driver board. Upon reading the schematics of the Power Driver board, the +12V power fed to J118 runs through test point 1 and LED 7 on the board. The LED is not lit and the test point reads < 1V. Fuse F116 also resides in this circuit and it has also blown. Checked all other fuses.. this was the only bad one.

So I replaced the fuse hoping that would solve the problem and as expected... it did not. Upon turning on the machine again, the playfield boards, motors, and LED 7 would work/light, but only for about 5 seconds before F116 once again blew and the motors and opto boards shut down accompanied by a faint but distinctive burnt electronics smell.

Also, some other anomalies, Captain: LED 5 (+20V flashlamp circuit) is also off (normally on) on the Power Driver board, and test points 6 & 7 (50V and 20V, respectively) also show near zero voltages.

While I'm not a complete dunce when it comes to electronics, my knowledge and hands-on experience is very limited and I'm at sort of an impasse. I'm not really sure where to go from here and I was hoping some enthusiastic STTNG pinsiders could lend some of their expertise on this.

Thank you!

Yes, I realized this a little after I posted - my coin door was open. So really the only issue is the 12V. I took the whole board out to check BR5 and it tested out ok. So I put the board back in, popped a fresh fuse into F116, and left J118 disconnected as you suggested.... and sure enough, the 12V line was stable and did not blow the fuse.

So I reconnected J118, turned on the machine with the playfield up, and was getting ready to detect where the smell was coming from when, to my surprise, the 12V again did not fail.

So the machine is working 100% again now, but not due to anything I did, unfortunately. Maybe just re-seating everything on the power driver board did it? Or maybe moving the playfield up and down loosened something that was previously shorted. In either case, I feel that this issue will probably come up again, and I'll again have to play Geordi LaForge when it does.

But thank you for your guidance, Pin_Guy.

That's apartment living for you. He gets so stir crazy sometimes he needs to get outside. All it takes is a small dog harness and A LOT of patience. But he loves me for it.