Have you replaced any drop targets with repros? The repros are a later design for target banks with switches on the back instead of on the bottom.

If you have, you'll notice the base of the target has a little ridge on it which prevents the target from pressing on the switch button as much as the original flat base does.

Minor vibrations cause the switches to open and close. The early SS code was not "smart" enough to ignore switch vibrations after the target is dropped and therefore, continues to score.

Try blocking the active switch too, see if the behavior changes.

i had the exact same problem on mine, i had to replace all diodes in the whole bank and then adjust all the switches to control it. Its good now, but when i just focused on the problem switch it kept acting up.

Unblock all of the switches, start a game, knock down a target, then pound on the playfield. If it scores every time you pound then either one or more of the switches is gapped too close or the target can't press on the switch hard enough to keep it closed.

Well I'm at a loss then. How would the game even know you dropped a target if your switches were blocked (from your testing in first post)? Other than movement/vibration what could cause a switch closure?

Like I said earlier, same exact problem... drove me nuts for a week. Targets scoring that weren't even down, when one of the others in the bank were dropped. Replaced all diodes, cleaned the contacts with a business card, and did major bending and adjustments to make better contact with switches.

Or you can spend 75 bucks and get 8 new of these...
https://www.marcospecialties.com/pinball-parts/ASE-2911-17

EDIT: This was happening with an Alltek board installed if that helps rule anything out.

If replacing the diodes doesn't work, I would suspect a bad PIA at U10.

Awesome to hear!!!! I was really hoping youd try it. I also have the Alltek on mine. Hasn't been a problem since I replaced all the diodes.

I had a bounce on mine and I really had to bend that switch around to compensate... it looks ugly but I bent the piece with the plastic pad way up so the target pushes it way down on the drop and its been great.

That's what you have to do, and it's more difficult with the repro targets due to the gap between the base of the target and the bottom plate of the target bank. Using a stiffiner on the switches would probably help.

I ended up epoxying plastic pieces to the base of the targets to make them flat like the originals.

I'm going to have to replace my switches on all my drop targets on my Mata Hari also. A few of them have now developed the same problem with runaway scoring. I've bent them every which way. They either bounce and score too much, or don't touch and don't score it all. It's not helping that every single drop target switch was assembled backwards by Bally. Practically every switch on this game was assembled backwards. Contacts not facing each other. I've replaced a lot of switches on this game because of that. I also have repro targets. I wish somebody would make these repros correctly.

Actually this may have solved my issue also. After adjusting the switch like crazy with mixed results, this bending the plastic pad way up seems to have done the trick. Maybe I don’t need those new switches just yet. Thanks guys for the tips.

Edit: spoke too soon. Problem is back.

I ordered 8 new leaf switches for the drop targets from Marco and it looks like they all came with the diodes installed backwards. Am I missing something here? Did I order the wrong switches?

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This was a first gen problem with SS drop targets. Unless the switches are perfectly adjusted and clean, vibrations cause multiple scoring. We eventually fixed the problem by moving the target switches to the side of the assembly and reprogramming the game to ignore subsequent target switch closures until the targets are reset.

Thanks. I guess trying to install a later style into this game is not practical. I'm going to flip the diodes around and try these new switches. If anything, I would hope the contacts facing correctly has to help. I may try gluing a piece of plastic to the bottom of the targets to make them flat like dothedoo did for his game.

Now I'm trying to make determine if either the old or new diodes are backwards. Can anyone make sense of this schematic?

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Looks like yours match mine. Strange that the switch you got is backwards.

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Thanks for the photo. It looks like the Marcos switches are backwards. Looking around the game it seems that the cathode side (striped) always goes to a tab that is empty. In most cases that's one of the rear tabs, but on the drop targets it's the side tab.

Are you going to contact marco about it, I wonder if they grabbed the wrong ones or if someone is just putting them together backwards

I will send them an email. I bought 10 of them (2 extra).

That sounds like a lot of work when certainly reprogramming the game would solve the problem. Got any images of those updated ROMs laying around? I'd love to burn new ROMs for my friend's game.

I'm not so sure it's backwards.

On the Bally switches, one of the blades has the solder tab at a 90 degree angle to the blade. The blades in the Marco unit look to have both solder tabs oriented in a straight line with the blade, and the extra mounting tab is at a 90 degree angle.

If that's the case, you just need to solder the (bare) common wire to each of the 90 degree tabs. Your other wires will get soldered to the tabs that have no connection to the diodes, as they were in the original configuration.

Ok, I understand what you're saying but what happens here? Each bank has one switch on the end where wires are on each tab. (First picture far right, 2nd picture far left). The other thing is I guess I would have to loop the bare wire over or around the switch. Correct?

IMG_1271 (resized).jpg

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I would replace the bare wire with standard wire and daisy chain the switches together. The wires on the end switches in your pics would also connect to the 90 degree tabs on the Marco switches.

Thanks

I would swap the diode orientation so they match the schematics. That way there's no confusion for anyone servicing this machine going forward.
.

I think BigAl56 was talking about later gen games. The 1982 Bally parts catalog lists the current part numbers for the Mata Hari ROMs that are already dumped.
It shouldn't be too hard to fix the code. Just need to bitmask of the drop target switches that have activated and then reset the bitmask when the targets are reset.

I believe it's already oriented to match the schematics.

The difference I can see from the pics is that the Bally switch has one blade with solder tab inline with the blade, one blade with solder tab at 90 degree angle and the extra mounting tab also inline with the switch blades.

The Marco switch has both blades with the solder tab inline with the blade and the extra mounting tab is at a 90 degree angle.

So while the diode looks reversed due to the orientation of the tabs, it is actually electrically identical.

So BigAl, did you work for Bally?

That would be the ideal fix.

Yep, I was the Bally R&D lab supervisor from 76-83. I know all about this drop target switch problem and all the attempts to fix it. Seems the target switches worked fine in the lab but then after getting a little dirty in the field the problems Zomby is having would start happening. The first attempt at fixing the problem was hardware, moving the switches to a side mount which it was thought was a more secure hold. At the same time one of the software engineers came up with a way to use software to fix a hardware problem by altering the code to register a target switch only once during gameplay until the bank was reset. I do not remember if we released an updated ROM with that fix. Have to compare Zombys ROM numbers with others that do not have this problem.

Zomby should first carefully examine the switch. St-2, which is the white blue wire, should daisy chain across all the switches. ST-2 passes through the diode from cathode(unbanded side of diode) to anode to the Ix wire when the switch closes. Zomby should examine the switch and confirm electrically it works that way.

The next step is to rifle through the Bally service bulletins to see if an updated ROM was cut for those games with this issue. That would include all preceeding games. Also, those target banks may have been drilled with pilot holes so the switches could be mounted on the side. Maybe someone with a newer style game could post a picture of the side mounted switches so we can tell if those holes exist and then Zomby could order newer type side mount DT switches for the target banks.

flame suit on.... but I feel like this is going off the rails, I looked up 4 different mata hari's and can see all the switches and diodes are wired and oriented like mine and phillyfan64's. It would be a shame to do all this re wiring just to hear back from marcos saying "oh hey sorry grabbed the wrong ones" or "oh shoot yeah our new guy Ted, put them on backwards"
Im with Quench on this one. Just flip the diodes.

Ah yeah, I see what you're saying. The lugs on the new switch are a different setup and changing the diode around won't work. The solder blade from the old switch stack that doesn't have the leaf could be mounted on the new switch to make them look/work the same as the old but it's a bit of work (would also have to cut the new switch end lug that has the diode). Not worth the trouble.
Just wire the common strobe line to the side lug where the diode anode (non-banded side) is.

The Service Bulletins book from 1978 (on PinWiki) lists Mata Hari as having ROMs E725-21 at U2 and E720-20 at U6. Ditto in the 1982 Bally Parts Catalog.
@BigAl56, do you have access to later service bulletins that mention any different?

Ok, Marco does not make the switches but offered a partial refund. However dothedoo is 100% correct. I just tested the new and the old switches with an ohmmeter. Turning the diodes around won't work electrically. It's confusing but to use these new switches, the diodes have to stay how they are. It would have been simpler if they just made the new ones exactly like the originals, putting the solder tabs in the original locations. This would have been very easy to miss. Thanks.

I’m going to have to double check all my new switches in this game to make sure I didn’t mess anything up. Everything works so I guess it’s all correct. I hope!

I actually did have the complete notebook of service bulletins at one time. I sold it off a couple years ago when I was 'downsizing' along with most of my remaining Bally paraphernalia. However those service bulletins are out there. All of the Bally distributors had them and at one time Bally support was passing out notebooks to keep them in. I would be surprised if someone does not stand up and offer to check.

I'm guessing all of their switch blades are made with the solder tabs inline with the blades. So they had to make the extra mounting tab at a 90 degree angle or else all three tabs would be on top of one another.

It's confusing, but at least you know you can make these switches work and they'll be more reliable.

That's awesome! That would've been a great job.

Well it's not too pretty. Not done yet. I just want to do the one bank to see how it works before I go any further. I still have to glue a little piece of plastic to the bottom of the drop targets since it is still not making contact. I bent them a little but don't want to bend the new switches all up. Found some plastic to use but the glue isn't working. I guess I need some epoxy or maybe model glue.

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I also have an Alltek board. I would be curious to know if it’s the latest rom. I’ll email them. I should have tried switching out the diodes. I’m not too happy with how this turned out and I’m not sure I’m going to do the other bank. I do want to try adding the tiny piece of plastic to the target bottoms. Why these targets don’t have flat bottoms is beyond me. Funny thing is I never had a problem with targets phantom scoring until recently. My problem was usually the well documented bricking problem.

Decided to redo this. Combined longer blade of the new switches with the short blade and “dead leg” of the old switches. This allowed me to keep the bare wire the way it should be. Contacts facing correctly now.

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That is exactly what I find myself doing, tear 'em apart and just reassemble to achieve original configurations.
WELL DONE!

You got it! Welcome to my world as it was about 40 years ago.

Thanks! Not tested yet. Waiting on the glue from Amazon to add a little plastic pad to the bottom of the drop targets.

BigAl56, what a great job that must have been!

What kind of epoxy did you use for this? I ordered some Testors model glue but I'm not sure if it will work.

I just used standard Locktite epoxy that you can buy at any hardware store.