I'm hoping someone can shed some light here.

I have a black knight with the lower right flipper that is just a tad too weak to make it up the left ramp. The flipper works fine and makes it all the way IF I bend the blade on the cabinet switch that grounds the UPPER flipper (so the upper flipper is no longer engaging when the cabinet button is depressed) The lower flipper has been rebuilt with plunger/pawl, coil stop (I swapped out the entire plate as well, so now I can use a coil stop) and new eos on both lower and upper.

I have filed the cabinet switch well with a point file. I will be picking up a new cabinet switch soon.

Ideas?

Thanks for the reply. Filing EOS and cabinet switches is perfectly fine for early solid state. They are high current switches. Now if they were fliptronic, or any other leaf switch on the game for that matter, card stock is the only thing you should be cleaning that switch with.

Yeah the black Connector blocks. There's one under the upper playfield and one at the head. I've done a few connects and disconnects. I even used a rotary tool and lightly burnished the inside of the female connector pins. No luck.
The voltage going to the coils is normal, so that points to a potential ground issue.

I figured out a solution to the problem, but it isn't a common one, and is rarely (I've never seen it) documented.

Snowyetti, All of the mechanics were properly replaced, I replace what needs to be replaced whenever I get a game.

In this case it was all about the cabinet switch, and staging the switches properly. Perhaps there is a grounding issue elsewhere but this could not be found. What happens is that if the upper flipper engages too soon, it steals power from the lower flipper, somehow. I'd love to be enlightened on this subject, because this isn't the only instance where this has been an issue. I discovered that if I bent the last leaf of the cabinet switch so that it would not engage the upper flipper, I could hit that left ramp all day long. So my solution was to bend the last leaf so it *just* makes contact with the middle leaf with a full button actuation. Then I bent the middle leaf so that it would effectively make contact with the first leaf much quicker. In other words, smallest gap possible between the the first two leafs, widest gap possible between the second two.

I just bought a batman forever. There are known and documented issues with specifically the right lower flipper. I had the same issue as seemingly everyone. The lower right flipper just can't make the ramp, especially 10 mins into playing the game. I did the same thing, sticking a piece of paper between the upper flipper cabinet switch contacts. Well would you believe it, I can now make the shot all day long. Regardless, I've ordered a stronger coil for that right flipper, as my staging trick didn't work there.

Anyway, may this solution find someone with the same issue down the road. And if anyone can chime in as to WHY this happens, I'm all ears... Er...eyes!