So, ever since I bought my Stargate, I've had an issue where, after a little bit of play, the left flipper becomes noticeably weak enough to the point where the right ramp shot is extremely difficult. I tried a few different things in an attempt to fix it, and while I was able to improve it somewhat, it still eventually becomes too weak to make the shot. The other day though, I realized that the issue might not be the flipper, but it seemed that other solenoids become weaker too. Left ramp shots from the upper flipper become harder, and the auto plunger fails to send balls all the way up the ramp more frequently when the game is played for longer. With this in mind, I tried a couple things.
First I cleaned all the relays in the bottom of the cabinet, something I haven't ever done. Of course, they were filthy! Now, I'm not sure If it's just me, but it almost seems like that made the issue *worse*. Whereas before I could usually play a couple good games before the right ramp became a struggle, now it seems to happen way faster. I don't know how cleaning the relays could have had such a negative effect, or even if that was the cause, but now I'm more desperate than ever to get rid of this issue once and for all.
One other thing I tried doing was swapping out the factory installed 110V red jumper in the transformer panel with the 120V orange jumper, as pinrepair.com says you should do. Doing this seems to cause the solenoids to start out weaker. I have yet to see the auto-plunger successfully send a ball all the way up the skillshot ramp with the 120V jumper installed. It can do it just fine for the first few minutes with the 110V jumper installed.
As a final note, I have not done grounding mods. They seem a bit complicated and other than this issue, the machine has been working just fine so I haven't really felt like they were worth doing. Unless, of course, doing them will fix this issue!
So, with all that said, what should I do next? What should I be checking to ensure the proper amount of power is being delivered to the solenoids? Any parts on the boards or power supply worth replacing?