Is there any issues replacing a flipper coil for one of lower resistance (such as a FL1-15411) in a system 11, besides possibly breaking plastics? Just a little backstory this is on a Black Knight 2000 and I am finding the upper playfield skyway loop very difficult to make. The ball tends to want to come down before going all the way around. Flippers have been completely rebuilt, the voltage at the coils was a little low and recently replaced the power aux board which did help. Not sure if I am missing anything else, or if just wear on the playfield has made it harder for the ball to get around as well when it was new.

Playfield is set pretty low currently just under 6 degrees much higher it basically will never go through the loop fully. In fact even with some of the bumpers removed at the end of the loop it still has trouble making it through at this angle.

EOS is gapped pretty close. I don't think I could safely gap it any closer than it currently is.

Hahaha yeah that's probably true!
Yeah okay so that's what I thought, but when I tried using a stronger coil on a Rottendog MPU board it actually blew a cap and killed a diode along with some other issue I'm still tracking down as it currently gets no power to the flippers now. I currently have the original MPU back in now after doing a separate repair to it but I just didn't want to fry something else.

So before changing the aux board the bottom right flipper was around 60v and the top right just under at ~59v. After changing it it's around 64 lower and upper is 63.5 or so. The EOS switches are new I actually replaced the he entire flipper mechanisms with the switches just to rule anything out.

Ah that's good to know and yes the rubber, but also even with the metal post by the loop switch removed it's a problem. I did find an old service bulletin a while back about bending some metal pieces in. I did this and it actually did help a lot with the ball lining up with the flipper but still feels a bit under powered. Besides that I checked the metal lining around the loop it seems pretty flat with just some expected wear.

That's a really good idea, I think I will change my setup that way as well. I have done some cleaning on the switch but I probably should go over it a little more just to be sure it's as clean as it can be.

That's good to know that isn't a normal thing to have happen at least. The only thing I can recall that maybe could have caused an issue is I discovered after the fact that one of the wires on the EOS switch was not making great continuity and needed to be reflowed as I wasn't getting high voltage, just the hold voltage.

Does anyone have any schematics to the Rottendog board by the way? I have been trying to track it when down and haven't turned up anything online and would really like to get it fixed.

Well it is doing that, but I mean if I were to push it in closer it would have trouble fully opening potentially. I'll admit I probably didn't do it the best way I still need to get something to properly check the gap as I'm just eyeballing it.

Sure thing.

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Yeah I'm sure you are right that it should be gapped more. Kinda going back to why I'm trying to figure this out, if I gap it more it starts to really feel underpowered.
I may swap the coil out knowing it shouldn't be a problem now and I'll re-gap it and see how it feels afterwards.

I'll add that to the list. That's a great point, I had read that those conical springs can cause issues before but I thought it was more of a premature wear issue. Hopefully all these changes should drastically improve the gameplay. Really appreciate all the advice!

Just a little update, I tried basically everything including upgrading coils, changing the return spring to the more modern style. Nothing fixed it.
I did some more testing shooting it and I finally discovered what was causing my issue. It's the wire gate at the top of the skyway loop that prevents the ball from coming back down the ramp. It seems to move easily but I did clean it up, for whatever reason it tends to direct the ball downwards so it doesn't complete the loop. With it removed the ball easily completes the loop now. Anyone else ever experience this, any solutions besides completely removing it?