Quoted from Pin-Pilot:
My High Speed Had the hum also. I was not intentionally trying to fix the hum but I needed a new power supply. I ordered a 3rd party Powersupply (don't recall the brand right now) instated it and the hum went away. food for thought. re-capping stock power supply may help as well.
1. So after opening up my High Speed and really looking at the Power Control board... I am scared of my pinball machine. I just ordered a reconditioned board off of Ebay that looks brand new for $60 and a set of 200 molex connectors off of amazon for $15 to fix this mess. Hopefully this will fix the loud humming noises on my machine and will make comfortable enough to sleep at night without worrying about the house burning down. This board was one of the last original boards in the machine. I'm sure someone will want a System 11 board to tinker with.
2. The volume on my high speed does not go below movie theater sound commercial levels. I may be imagining things, but it seems the sound effects are way louder than the music when I play. The simple fix should be to just add a supplemental potentiometer (primitive volume knob/resistor) in the wiring before the stock volume knob. Would I add that knob below the left, middle, or right connector?
3. My playfield really isn't that bad when I step back and look at things. I have sourced another original pop cap and center plastic off of ebay. I may attempt a little touchup here and there (like the red in the drain on the left) but will probably just leave it as is as I'm going to have to let this (or my new Taxi) go when I get the call for Rick and Morty. The only thing that's really bothering me is the mylar by the right drop... maybe some glue... If I did anything beyond that it would be a hardtop, but I don't know that this machine warrants it.
4. Machine plays pretty much perfectly (except for the volume). I did notice that since I leveled the machine when the ball pops from the capture hole to feed the right flipper, it tends to bounce off of the side rail and make the ramp shot about impossible. I'll have to fidget with it and see if I can adjust it.20200127_194432 (resized).jpg20200127_193609 (resized).jpg20200127_194254 (resized).jpg