Usually under test, the Hold circuit is not strong enough to move the bat on it's own. You lift it by hand and the hold circuit then keeps it raised.

That's Fliptronics, right? Try swapping the flipper cabinet button opto boards left/right. Does problem move to other side or stay?

So swapping the cabinet switches resulted in *both* flippers working normally, then the *right* one went limp again?

Do you have 50VDC on all three lugs?

Reseat J212 on WPC board.

Reseat ribbon cable from WPC J211 to driver board J102 and J119/J120.

OK. 50VDC on all three lugs when it flips weakly?

While it is flipping weakly, connect a clip lead jumper to the ground braid on the side of the cabinet. [CAUTION] Don't let the free end touch anything accidentally!

Quickly tap the free end to PDB J 120.12. It may spark a little, that's normal. Just don't have any naphtha fumes hanging around. Do you get a strong flip?

Now repeat that same test with the clip lead to WPC/CPU board J212.12. Do you get a strong flip?

I just watched the video again and the right flipper button is making a ka-click noise the left doesn't. Is there something weird going on with that cabinet button? It does sound/behave like a mechanical problem (slow return).

Scared Stiff R flipper (resized).png

You mention that you replaced "all optos". What did you use for replacements? These are special types and even some replacement boards being sold out there have the incorrect types on them and could cause these issues.

The thing that is puzzling is that you swapped flipper cabinet buttons and recovered the failure temporarily. YET, you can ground the flipper cabinet switch and it still fails. I would swap those cabinet buttons again, just for clarity to see if they affect the symptom again.

If it recovers then goes weak again...

Those boards you used are probably the problem.

The original optos used have inbuilt Schmidt trigger circuitry and are unobtainium now.

The very first replacement boards I made used standard optos as replacements (just like the ones you are using very likely) and these worked in 60% of cases BUT not in every machine. I had to throw out the first batch of 100 sets we made for this exact reason.

The issue is standard optos don't switch down hard enough and hover around 2V5 which is half rail for TTL and so the switching is unreliable. This can cause all sorts of weird results such as fluttering flippers, weak flippers, driver transistors blowing etc. In some cases they will work just fine.

If you look at the boards I currently make you will see I have added a buffer transistor after the opto to force the switched rail harder and this solved the problem totally.

Actually on "Pinball Bash" this topic was covered a few years back in detail and my board was mentioned as one that had solved this issue.

Replace the boards (or refit the originals) and your problem will very likely be resolved.

I wouldn't keep looking elsewhere for this problem until you have ruled out these replacement boards 100% AND trying them in another machine will NOT give you the answer. You can try measuring the voltage at the output of the flipper board when idle and also when the flipper button is pressed and tell us what you get.

Look at the meter voltages in bench testing pictures of the Type 1 flipper boards below (both boards use an identical circuit) and you will see what I am talking about with the output switching. Homepin boards are available from "Johns Arcade" in Australia and "Pinball Life" in the USA.

image_0005 (resized).jpg
indicators (resized).jpg
typeone1 (resized).jpg
typeone2 (resized).jpg

You could 'ground' the metal tab of Q91 to trigger Q90.
If this activates the hi-power coil, it could indicate that Q91 is faulty.
If it doesn't activate the coil, a broken trace is a possibility.

The picture below is from the SS manual and illustrates what I am talking about.

I have just found a set of these boards in the factory that I didn't know I had here. If you PM me your full name and address details I will get them off to you so you can try them.

Type2parts (resized).jpg

After you replaced Q90, did you perform this test again and what was the outcome ?
Trying to find out this is a coil drive problem, an opto switch problem or both.

Getting 2V5 tells me the optos are not the correct type and therefore are not switching hard enough. Compare your results with my pics above. I wouldn't waste any more time looking further, I believe you have found the problem.

Your boards are packed and will be in tomorrows postal run.

I meant the test T.12 in the menu.
Grounding the transistors as you did gives the correct response. (Q90 nothing, Q91 normal flip and Q92 slow to hold)

You're very welcome. Happy for you to try them and confirm if they fix your problem. All I ask (if they work) is to cover the postage.

Otherwise it's my risk.

Zaza - I have seen this issue before. There are a lot of aftermarket boards being made and sold that use ordinary optos and they work in some machines but not in others for the reasons I outlined above.

I was very lucky that this issue was brought to my attention before I sold too many and I was able to redesign them and replace those I had already sold.

It looks like it is the 3rd option

I'm wondering if your coil is getting hot and causing binding to occur.

Glad you received them and sorry they didn't fix your problem

Sure is time to have the boards looked at, maybe by someone who does a lot of repairs????

The only other things I could suggest are accurately measure the 50V supply to the coils (74V) before and after the problem shows and make sure it doesn't change, not even by a few volts. After that maybe replace the fliptronics board with a new board if you haven't already?

Don't worry about the boards cost, that was the deal, no fix, no pay

Please keep us posted with your progress.