So the bends basically are just raising the 'up' position of the targets, right? The targets only have a small nub in the center that catches on those bent edges. If that's the case I can't figure out why this would have a noticeable effect on bricking(?)

Maybe the bend actually really is reducing how much of the target's nub is grabbed, because of the way the edge is bent.

Like this... but it's a tiny bit exaggerated.

I really can't see the 'ramp' effect having an effect. The target's nub is flat on the bottom. When the target is hit it's still only going to travel horizontally along whatever edge it is resting on, bent or not.

I worked on some Stern and Bally drop units but never noticed this kind of bending so my guess is it is not factory.

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The 'bump' means the target latches a tiny bit higher too, so they should spring downward a tad faster too. And being a little higher it could be slightly changing the leverage point on the target when it is bent back by a hard hit, how it is hitting the rubbers behind it etc. Could be a combination of effects I guess.

I personally researched this when I was at Bally in the 70s. We invested in a Polaroid super-slow-mo instant 8mm camera projector, which was SOA at the time. This allowed Desi D' Percel and myself, actually Desi did the work and I watched, to examine the way targets reacted when hit by the ball and learn why they didn't always fall. When slowed down we learned that when a ball hits the target head on at fast speed the top of the target bends backward into the rubber behind it and bounces back forward before the spring can pull it down. There was no real fix for the problem without a redesign or finding an alternate material to make the targets out of. Any redesign could potentially infringe on Gottlieb's patents so the only fix implemented was adding a ledge to the top of the target.

Best fix I know to this date is to replace the targets and springs with new parts as the legacy parts are probably worn and dried out.

I could be wrong but I seem to remember seeing pictures of someone here a few years ago who glued stiff steel wire in the back channel of his drop targets to minimise this issue of them flexing?

I tried that on one of my Lightning's center drop targets, couldn't really see any improvement. And other things like stronger springs. Never have been able to completely lick the problem.

I tried this on the Mystic I just rebuilt.

New Playfield, new “guaranteed to brick” drop targets …

Works well! The drops do drop pretty consistently.

Will continue to use going forward. Thanks for the tip!

rd

I have a Stern drop bank with repro drops. If making the bally bank mimic the stern one helps the bally, then what is it about stern repros that make them brick? They already have the "more ideal" shelf, so its something to do with the targets themselves, right?

I find the ones from PBR brick just fine if they take a hard direct shot. I strongly suspect the plastic used today is just to far flexible and the head of the target whips back and forth so fast the catch doesn't release.

Are there any guesses what family any era of drops were made with? I had a drop break on my Ice Fever and when I got a rep!a cement set they felt like ABS, but the drops for my bally/stern games feel softer for sure.

Guess I hit quote instead of edit when I went to fix a typo...

BigAl56 I want to say its awesome to hear from they guys who did the testing. Are there any other component tests or problems that you can remember or share?

Far too many to list here. As time goes by I chip in whenever someone revives a memory.

On Bally games, all D/T rubber rings are doubled.
If the pictures here are of your game, then, one needs to add a second rubber ring
to the back sides of each D/T assembly.
Note:
with repro playfields the posts are sometimes not positioned to exact placment
as the OEMs are.

On a side note:
I was hopping to try and do a modified linkage to the plastic
drop target. I was thinking of an extra spring from the linkage
to the bottom base plate.. like what Gottlieb has done.

Unfortunately there is no tried and proven fix for Bally DT bricking. If the targets and springs are new just enjoy the game as it is what it is. If anyone comes up with a documented fix for Bally target bricking please post it in a new thread.

It would be interesting to produce some repro targets using different plastics to see how they compare. No, I don't have a clue how to proceed with that...

Have you tried these from Swinks - I think he's down under, and reading the thread below it sounds like these work.

As soon as I figure out how to make a link to a topic, I will, but for now....

Classic Stern Tombstone Drop Targets - now available

Thanks for pointing that thread out!

Here's a link: https://pinside.com/pinball/forum/topic/stern-tombstone-drop-targets-13a-11-any-interest

Gottlieb owned the patents. Bally was limited in what could be done with their available tooling. It was decided the targets worked well enough as-is. If anyone would like to embark on an upgrade project I would start with Gottlieb and reverse engineer. Just don't infringe on any active patents that PBR controls.

Even with Swinks targets, the center bank was still bricking on my 81 Lightning. That bank gets mercilessly hammered on this game, with the factory flippers needed to make the ramps. Not as much as the repro hooded targets, but still bricked sometimes. The above-mentioned trick I tried was on the metal drop target ledge - I sanded the top edge with very fine sandpaper to remove any possible roughness and polished the ledge shiny with buffer wheel and polish. Those ledges were simply punched out at the factory and not 'finished'.

I can tell the difference when pushing the targets with my finger, target moves smoothly before dropping. Before they felt hitchy/grabby as they moved off the ledge. In fact after the smoothing I found one of the Swinks target's ledge nibs had gotten so chewed up by the previously rough ledge, now it wouldn't even stay up on resets!! I attribute this to that particular spot on the ledge being extra rough + the somewhat stronger springs I had installed months ago. Other two targets were fine. Bricking seems to be much rarer now, not annoying me anymore. I figure the unfinished edge of the ledge was helping the targets get snagged as they bounced forward after a hard hit. Should also prevent excessive wear on the target nibs especially if you are using stronger springs. Not saying this is a total fix, but it helped.

Entropy of the universe, man. It's a bitch.

Many years ago I had a Stern F2000 that the count down bank would not
work consistently.
The metal links were worn out..etc. I re-drilled the main
pivot hole and added the nylon snap bushings.

In all it fixed the assembly, but made the targets "drop" kind of stiff and very controlled
instead of quick and jerky.

Have you tried the updated tombstone targets from swinks ? I know he makes them for stern. Not sure if he has them for Bally though.

I think he has hooded ones too.

The PBR and then Planetary Pinball sell the classic stern remakes with hoods as the mold was modified for the later sterns with hoods and therefore the non-hooded mold does not exist anymore. PBR had them made with more flexible Nylon which contributes to the issues of bricking.

When I originally reverse engineered the Classic Stern Drops a friend sent me a couple of bank with the drops and one was with the rib and other without the rib and the drop assembly had a plate reverse to accomodate the non ribbed classic Sterns. I offer both on Shapeways but only the ribbed from myself as more common but can get a much better price on bulk orders.

I also modelled the 80's Bally drop which is up at Shapeways but not cheap as Shapeways price / print fee is high.

When I compared the Classic Stern and Bally Drop targets digitally the similarities are:
- they share the same shape and face tilt angles and holes are the same as well as the target shelf edge (where the rib leads up to)

The differences are:
- Bally has the re-enforced mid hole where the spring attaches
- Bally has the extra nib on the bottom for different switch activation
- Bally has not rib but some classic stern also had no rib based on what was supplied to me
- Classic Stern target stands taller but funny enough it is the same distance as the Bally with the nib at the bottom
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