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.

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 : )

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.

Fortunately weak flipper strength can be corrected....

61B6A249-934A-4C3B-AB80-98742649354A (resized).jpeg

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

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.

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

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

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

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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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.

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.

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

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

.

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.

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.

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.

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.

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.

I'm having this same problem with my Ripley's. Do you have a link to that transistor perchance? Not finding on Pinball Life.

do a search on Pinball life for irl540, you'll get here:

https://www.pinballlife.com/transistor-replacement-for-22ne10l.html

Resurrecting this thread is amusing, I've had three different weak flippers on three different Whitestar boards caused by previous work where someone substituted a transistor that 'worked' for a flipper driver... and it didn't work well enough.

'To really mess something up requires a technician.'

Make sure you use IRL540, and you won't be the source of a future technician pulling their hair out trying to figure out why the flipper is weak.

Good luck getting your flipper problem resolved!

Excellent. Thanks