WPC flipper opto vs microswitch?

I’ve just bought a Dirty Harry and the flipper opto boards have been replaced by microswitches. Clearly this would affect the feel of the button press, however, I think it is also affecting the performance of the flippers. My rational brain says there shouldn’t be any difference since a digital signal is a digital signal, the button is either on or off, however I am convinced there is a difference and so I am considering putting optos in. Does anyone have any thoughts that shed light on this?

I am actually interested in this as my container WCS94 has had the same done… Though opto often have issues with the spring board so I usually like leaf switches better?

I have an opinion since I own several BLY/WMS games.

The best BLY/WMS flipper switches made (IMO) were the opto switches on WCS (early ~1994). The games used a black plastic mould that didn’t require any adjustment, other than not turning the wood screws into the cabinet so tightly that the switch always read “closed”.

There were (generally) four varieties of WMS solid-state flipper switches:

  1. Addams/Getaway; a mechanical leaf switch (copper color) which required adjustment to not feel stiff.
  2. Whitewater/Judge Dredd; an optical metal switch with a (mostly) metal blade (steel color) which required adjustment to not feel stiff.
  3. WCS/DemoMan … Shadow/Dirty Harry/Theater/NF/Jackbot/Indy 500/JM/Congo; an optical switch with a black plastic blade. This design did not require much adjustment, if any.
  4. Attack from Mars …; an optical switch with a white plastic blade and a blue spring-steel backing. This did not require much adjustment, but it always felt stiff, unless you removed the spring-steel.

To the CPU, there’s no real difference between any of the switches. The logic for the opto should be inverted; it should read open when the opto is blocked, so it should be fine.

Around the time of Shadow and Dirty Harry, WMS experienced some problems with their flipper switches such that if you held the button in for a decent amount of time (say 30 seconds or so) and then released the button, the plastic blade would be very slow to retract to block the opto. This resulted in a flipper feel that most better players described as “sticky”.

It took WMS an additional year+ from the time they first identified the problem to the time they “corrected” it. AFM flipper switches used a white plastic blade with a blue spring-steel backing. These switches had a much stiffer feel than the original “non-sticky” black plastic (WCS) blades. And they didn’t stick! But the compromise was that you lost some of the feel.

If your Dirty Harry has mechanical leaf-switches for the flippers then my guess would be that the person who owned the game prior to you was annoyed enough by the “WMS sticky flipper syndrome” that they took it upon themselves to correct the problem. But that’s just a guess.

And if that’s the case then I can’t say that I blame them.

If you want your game to play as close to “original” as possible, then re-install the black plastic blades with the opto boards. Just make sure the blades aren’t the ones that stick all of the time.

if you want to just play the game and have fun then I would just leave it as is.

You can usually adjust the mechanical switches to whatever feel you like.


Also good to keep in mind is that the opto style switches had two sets of switches on each side. One for lower flippers and one for upper flippers. Even if a game doesn’t have upper flippers a lot of the time it will use the second switch as the lane change.

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