(Topic ID: 255158)

Lesser known causes of a weak flipper...


By robx46

14 days ago



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  • 35 posts
  • 20 Pinsiders participating
  • Latest reply 2 days ago by Scrimmbo
  • Topic is favorited by 5 Pinsiders

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#1 14 days ago

OK so I'm stumped here. I have an Elvis that I'm convinced has a weaker lower left flipper than the right one. Not my first rodeo. The usual fixes didn't work. Flipper assembly is clean, new sleeve, moves freely just like the other. EOS is properly gapped. Then I went further, replacing cabinet flipper switch, EOS switch, coil stop & when that didn't help I even installed a new coil (of course same coil as the right). No improvement.

I've even noticed that the left flipper "gives" more easily when in the up position & a ball comes down to hit it & backhands are weak. I can make the ramp shot with that flipper, but it has to be clean & it doesn't zip up the ramp like the right flipper sends it. So I don't think I'm crazy. Also I've inspected the upper left flipper coil, changed sleeve on that. All is good & that seems plenty strong. What else is there to check?
Is it possible anything on the boards or in the wiring could make a flipper somewhat weaker?

#2 13 days ago

Could it be a mechanical issue like this:

https://pinside.com/pinball/forum/topic/flash-gordon-saviors-of-the-universe-club/page/21#post-5242246

Of course, Stern flippers are entirely different, but I’m just wondering if some part came undone in a similar manner.

#3 13 days ago

Just because you replaced leaf blade switches on flipper buttons and EOS, don't assume they are good. The contact points ( look like rivets ) on the end of the leaf, could need a good cleaning. And each contact might not be making a good electrical contact with the leaf blade.

Put a meter on the lugs, hold the flipper button to close them, and see if it's a dead short, or shows some ohms.

LTG : )

#4 13 days ago

First, do as LTG says, because he is LTG.

Then, check what kinds of switches you put in the cab. Does Elvis use those crazy crossed switches from Stern? Are they the same type on both sides?

I’d also pull out the linkage to make sure it isn’t binding, Has no extra play, and has that spacer between the bolt and the plastic.

After that, I’d be swapping parts left to right. The coil, the switches, right down to the transistors. At some point of swapping, you will find the defect.

#5 13 days ago

Thanks for the tips. I do get the same behavior with 2 different sets of cabinet & eos switches, both I made sure are clean as can be. & 2 different new coils. I feel like I've ruled that out. Mechanically I took things apart. Everything is there & clean & freely moving. The left flipper just doesn't have the same low power (up) hold strength as the right. I even made the eos open a lot wider than it should be, but it is giving out long before those contacts touch again. If I'm holding the ball on left flipper & go for a backhand shot to left or center it seems pretty strong but it is shots to the right & far right that appear weak. Not sure what that tells me but that is how it seems.
Is it possible for a transistor to cause something like this? Hate to start messing with the boards if that isn't a real possibility.

#6 13 days ago

Fortunately weak flipper strength can be corrected....

61B6A249-934A-4C3B-AB80-98742649354A (resized).jpeg
#7 13 days ago

You might not be looking in the right place: you said the flipper assembly is clean, but you’ve been focusing on the flipper drive power. Have you checked the flipper bushing? Sometimes they can be subtly cracked, not visible without removal and inspection. When you try firmly wiggling/tilting the flipper from above the playfield, does it have any more looseness or range of motion than the other flipper? It would explain different apparent strength in different shot directions...

#8 13 days ago

Also ensure you have the proper vertical gap on the flipper bat when installed. This gives people a lot of trouble.

#9 13 days ago

This is a 2 lug flipper coil right? That means the eos switch doesn't cut power to the pull in winding it tells the flipper board that the flipper is up so it can modulate the voltage to the flipper.

I'd hook a dmm to it on VDC and see what the voltage averages out to on the bad flipper with it in the hold position and then do the same on the good flipper.

Tech guys. Please let me know if I have the wrong assumption in how these Stern flippers work.

#10 13 days ago

You could disconnect the top left flipper coil, play it, then see if it makes the ramp.

#11 11 days ago

Thanks everyone, followed all the tips so far still no luck. However I did find something unusual. The EOS, when flipper is up, with game off, does what it should. No continuity. However, with the game on, the switch acts as though it is still making contact even though I can clearly see that it physically is not touching (again confirmed by the fact that there is no continuity there with the game off). Sooo... I have a board issue or short somewhere? I'm really not sure what to make of this or how to troubleshoot. This is a first. I'll look up some schematics but if anyone has any suggestions please let me know.

#12 11 days ago
Quoted from Phat_Jay:

Fortunately weak flipper strength can be corrected....[quoted image]

"Call your doctor if your flipper is stuck up for over four hours..."

#13 11 days ago

Have you checked the bat itself? I've had weak flippers and the bat itself was cracked. Also coil bushing like someone else said

#14 11 days ago
Quoted from Butch2099:

Have you checked the bat itself? I've had weak flippers and the bat itself was cracked. Also coil bushing like someone else said

I did check the bushing & it is fine, so is the bat.

#15 11 days ago

When all else fails i replace the part pictured. Referred to as solenood bracket. This part often becomes egg shaped in the center. Plunger not centered when energized. Ive replaced on older games like bk, firepower and get 20% more power sometimes after replacing everything else.

This part often gets overlooked when doong flipper rebuild.

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#16 10 days ago

Mechanically I've checked literally everything. The only issue I've found is that the game software is not detecting the EOS as being open even though it clearly is. It does on the right, but not the left. & that explains why the left flipper is experiencing this "foldback" (as the manual calls it) but not the right. Must be a board issue on flipper board or MPU, I'm just not sure how to tackle it.

#17 10 days ago
Quoted from robx46:

Mechanically I've checked literally everything. The only issue I've found is that the game software is not detecting the EOS as being open even though it clearly is. It does on the right, but not the left. & that explains why the left flipper is experiencing this "foldback" (as the manual calls it) but not the right. Must be a board issue on flipper board or MPU, I'm just not sure how to tackle it.

Apologies if you already mentioned this, but I'm presuming you've toned out the wiring all the way back to the harness? Perhaps the wire is pinched or otherwise able to be "closed" despite the switch being open? Also, maybe a break in the fishtape allowing conductivity between the two halves of the switch?

Just throwing stuff against the wall, as it seems you've covered the more obvious bits.

#18 10 days ago
Quoted from cjchand:

Apologies if you already mentioned this, but I'm presuming you've toned out the wiring all the way back to the harness? Perhaps the wire is pinched or otherwise able to be "closed" despite the switch being open? Also, maybe a break in the fishtape allowing conductivity between the two halves of the switch?
Just throwing stuff against the wall, as it seems you've covered the more obvious bits.

Well the switch does read properly as opened or closed when the game is off. But when the game is on, switch acts as if it is always closed, testing the same way.

#19 10 days ago

Have you replaced (with brand new parts) the most important part, the flipper plunger/link/crank assembly yet? Any "slop" in that assembly is "lost motion" which will weaken flipper action mechanically.

#20 10 days ago
Quoted from KenLayton:

Have you replaced (with brand new parts) the most important part, the flipper plunger/link/crank assembly yet? Any "slop" in that assembly is "lost motion" which will weaken flipper action mechanically.

Yes. That is why I'm posting because the typical things didn't work.

#21 10 days ago
Quoted from robx46:

Well the switch does read properly as opened or closed when the game is off. But when the game is on, switch acts as if it is always closed, testing the same way.

Your checking the switch to ground and not just across the switch contacts?

#22 10 days ago

I’m no expert, but I think this could be the result of a shorted diode in the switch matrix. Try opening normally closed switches in the same row or column, and those in possible “corners”, to investigate.

#23 10 days ago

Maybe Flipper feels weak because he stayed up late partying with SpongeBob?

#24 10 days ago

.

#25 10 days ago
Quoted from smsteve:

I’m no expert, but I think this could be the result of a shorted diode in the switch matrix. Try opening normally closed switches in the same row or column, and those in possible “corners”, to investigate.

Although I don't have a manual for this game, I beleive all SAM system EOS switches are direct grounded switches and not part of the switch matrix.

#26 10 days ago
Quoted from robx46:

Then I went further, replacing cabinet flipper switch,

Did you make sure to use the proper cross-contact (Self-cleaning, lol) cabinet switch? Elvis had a bad batch of cab. Switches to begin with, and I’ve not seen anything but the proper “Stern” switch give good results.

#27 10 days ago
Quoted from DNO:

Did you make sure to use the proper cross-contact (Self-cleaning, lol) cabinet switch? Elvis had a bad batch of cab. Switches to begin with, and I’ve not seen anything but the proper “Stern” switch give good results.

Yep, cross contact.

#28 10 days ago
Quoted from Pin_Guy:

Although I don't have a manual for this game, I beleive all SAM system EOS switches are direct grounded switches and not part of the switch matrix.

I do think this is the case. This is "whitestar modified", but the EOS are NOT part of the switch matrix.

1 week later
#29 3 days ago

Problem solved. It was indeed a board issue. I replaced the transistor, which had been replaced before with substitue for IRL5040N, the NTE variant (which I read here isn't as good) NTE2987. Replaced it with IRL5040N & thankfully things seem ok now. It was making me crazy!

#30 3 days ago
Quoted from robx46:

Problem solved. It was indeed a board issue.

Good job tracking that down! And thanks for sharing, and closing the loop.

#31 3 days ago
Quoted from robx46:

Problem solved. It was indeed a board issue. I replaced the transistor, which had been replaced before with substitue for IRL5040N, the NTE variant (which I read here isn't as good) NTE2987. Replaced it with IRL5040N & thankfully things seem ok now. It was making me crazy!

Glad this worked for the OP, but for my own education can someone with more electrical circuit design explain why changing out that transistor would affect change? From the explanation, everything is working besides the flipper strength. Wouldn't that mean the cabinet switch is being seen by the CPU and the proper signal to turn the transistor "on" and fire the coil is happening. So why would the transistor somehow limit the applied voltage to the coil, shouldn't it only apply whatever is feed from the 50V circuit or nothing?

#32 3 days ago
Quoted from Apex:

Glad this worked for the OP, but for my own education can someone with more electrical circuit design explain why changing out that transistor would affect change? From the explanation, everything is working besides the flipper strength. Wouldn't that mean the cabinet switch is being seen by the CPU and the proper signal to turn the transistor "on" and fire the coil is happening. So why would the transistor somehow limit the applied voltage to the coil, shouldn't it only apply whatever is feed from the 50V circuit or nothing?

I'm honestly not sure myself. The only other thing I did was fix a cracked solder joint on the connector that these EOS switches ground to on the power driver board, but according to the schematic the pin I fixed wasn't part of that circuit, which was further down in the row. As I mentioned, through searching I did find another thread here on pinside that mentions those NTE replacements just aren't as good. No explanation as to why. But after reading it I replaced that transistor even though it tested ok. Glad I did.

#33 2 days ago
Quoted from Apex:

Glad this worked for the OP, but for my own education can someone with more electrical circuit design explain why changing out that transistor would affect change? From the explanation, everything is working besides the flipper strength. Wouldn't that mean the cabinet switch is being seen by the CPU and the proper signal to turn the transistor "on" and fire the coil is happening. So why would the transistor somehow limit the applied voltage to the coil, shouldn't it only apply whatever is feed from the 50V circuit or nothing?

Transistors also limit current. It's possible it wasn't allowing enough current fast enough or ramping funny.

A transistor is not the same as a hard switch.

#34 2 days ago

The NTE replacement isn't quite an exact replacement. It will work, just not as good as it should. Best to use the original transistor number part.

#35 2 days ago
Quoted from robx46:

Problem solved. It was indeed a board issue. I replaced the transistor, which had been replaced before with substitue for IRL5040N, the NTE variant (which I read here isn't as good) NTE2987. Replaced it with IRL5040N & thankfully things seem ok now. It was making me crazy!

Wish I would have seen this thread earlier, had the same exact problem with a Ripley's Believe it or Not a while back. Sure as shitski it was a NTE2987 causing the problem.

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