Quoted from dr_nybble:I tried to fix my ball hangups last night. I have the rubber on the VUK wireform and pushed the Cliffy up against the ramp so there is no ridge. Sadly I am still getting ball hangups. The reason is that the ball guide and ramp edge don't line up so the ball hangs up against the edge of the ball guide.
Has anyone bent the ball guide to fix this? Looks like 2-3 mm would fix it.
Search this tread because i have some pretty detailed posts about this issue. I've done hours of work on this and I'll give you the cliff notes of my findings.
First, I've manged to set up my game so that rubber washers are not needed to prevent the ball spin. The first thing to do is make sure that the metal VUK guide is correctly set. There is a hole in the metal ball-guide apparatus (on the lower playfield) where a "leg" on the metal VUK guide/cage needs to be inserted. Also, I've found that some washers (I think on the side closest to the translite) angle the VUK guide enough to prevent the spin. I'm pretty sure I have a post in here that gives some more detail. All of the VUK guides are probably a little different so it may just be that mine is bent right, but regardless, I've got mine set now so there's no need to fool with washers.
Second, make sure your game is leveled correctly. You need to level White Water with the upper playfield OFF, with a level near the back of the lower playfield (you need to check the front too but that's easy to get to).
Third, after LOTs of testing, I found that it was ultimately my plastic ramp edge causing the hangups. I observed the exact same thing you did, and it looked like the ball was getting hung up on the side, where the plastic ramp meets the metal vertical ball guide. I spent hours trying to adjust the ramp setting (washers on one or the other side, using tape to angle the sides in, etc.) but no amount of adjusting fixed the hangup. How I ultimately figured out it was the ramp lip was that I removed the plastic ramp from the game entirely and put a pinball on it by hand: I found that the ball just liked to hang up right on the edge of the lip (almost like when you overfill a glass of water and the water creates a "bubble" above the top of a glass rather than trickling over the edge.) So ... I got out some sandpaper and sanded down that sharp plastic lip until the ball tended to slip off the end of the ramp rather than getting hung up. Then I used finer sandpaper to smooth out my work and then did the old Novus 3, 2, 1 treatment to smooth everything out. When working the ramp I would do my best to try to find a way to MAKE the ball get hung up on the end of the ramp and then work the area more so that I could no longer effectively do it. By the time I was done it was still possible for me to get the ball to hang, but it was WAY more difficult than how I started out. I figured that once I added the natural tilt of the game to the equation the ball would no longer hang. Lastly, when I reinstalled the ramp I thoroughly tested the area as I was setting the ramp (BEFORE YOU TOTALLY REASSEMBLE and while you still have good access to that area). I would use my hand to place the pinball in that area and try to get it stuck, then adjust if needed. Challenge yourself to try to get the ball to hang and if it becomes very difficult or impossible for you to get the ball to hang then you know you've done your job.
I honestly have not had a problem since. It's been over a year since I did this and I've only had a handful of times (less than 5) when the ball has hung back there. Even then, a small nudge would get the ball to move. I can't remember when the last hangup occurred, it's been over 6 months.
Of course all of this requires significant disassembly, which you should be doing periodically to clean the game anyway. I tend to do a full breakdown and cleaning about once every 2 years. When I reassemble I pay very close attention to that area and make sure I roll test with a pinball before full reassembly to make sure that area is squared away. I struggled with this for YEARS and it was ultimately the sanding and smoothing of that ramp-lip that fixed the issue.