Hello Everyone,

I'm currently working on my 1990 Bally Dr. Dude pinball machine, I've made a ton of progress and the only issues I really have left is a few banks of flashing lights that do not light, and my knocker does not work.

Lights - The banks of lights that do not work all seem to be tied to the same transistor (Q54, and I've been told to test Q53 as well). Today I tested Both Transistors and they seem to be reading fine. I'm not sure where to turn next on how to fix these lights.

Knocker - When I got the machine the knocker coil was very melted inside, preventing the metal shaft from moving inside it. I purchased a new coil and tested it and still is not working. I've been told that the transistor that is tied with the knocker is Q23. I tested Q23 today and has a good reading, I'm not too sure where to turn next on why the knocker is not firing.

Any tips or comments much appreciated, not sure where to go next on fixing these issues, thanks for any feedback!

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Thanks Grumpy, I'll do all of that and let you know the results!

@GRUMPY, I was able to fix the light issue. I found that the wire inside the Molex on 1J-7 pin #8 was not pressed in correctly, I re-pressed it in it with the black tool that presses in the wires in the connector firmly and 1J-7 pin 8 now has continuity and all of the lights work!

As for the knocker, I double checked that all of the wires coming from the knocker have continuity and it all seems good. Like I said in the previous post, I tested Transistor Q23 that belongs to the knocker and got a good read. You mentioned that transistor Q2 also controls the knocker, when I tested Q2 I got a reading that seemed very high, in the diode setting on the multimeter I got a reading of 2.978 and it continues to rise for a second then reads ".OL". Compared to other transistors this does seem high. Does this mean that transistor is bad and it was the reason the Knocker melted? Also, I'm not sure if it's the issue because the knocker would not fire at all, Since I get a quick high reading when testing Q2 before it goes to "OL" shouldn’t the knocker still fire? Also, one of the fuses on the AUX board where the knocker transistor Q2 is located looks a little odd, but it still tests good. A little confused on this one, not sure if I need to replace Q2 or not and if it will fix the knocker not firing.

Another Issue I've came across is that one of the lights on my Dude Meter does not light, the one on the very top for "Super Dude". I've tested continuity for 1J7 Pin #9 and all seems well. I even took off the small board where the lights go and tested all the diodes on it and all seems okay. All of the other lights light just fine on that board connected to 1J7 pin #9, just not that top one that belongs to "Super Dude". I tested the bulb belonging to the Super Dude Spot and it works fine. I've tried bending the little connectors on the light socket to get a better connection but still nothing, I don’t think adding solder to where the connectors touch will do much either. Any ideas?

Lastly kind of a random question, but a few of my mylar stickers on the lights on the playfield have begun to bubble. Is it safe to take off the mylar sticker and put a new one on to get rid of the bubble?

Thanks for any comments or replies/tips it's all very much appreciated, this machine has a came a long way with all the help here from Pinside <3
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Thank you GRUMPY once again for the kind words and tips, I will do all you said and report back!