Templates attached - Word and PDF formats.
Each square is 0.5x0.625 inches with center-line on fold. Each sheet modifies 180 switches.
I found that the squares folded to 0.25x0.625 work well for Step 1 for
all three types the D4 series of switches with coil springs only. (For these switches, you want to ensure the paper stays below the "lip" on the cover assembly for the microswitch). For the Cherry Happ K-series switches, you want 0.4x0.625 folded to 0.2x0.625 or single sheets of 0.2x0.625 - Templates added for these, more below.
Happy modding!!!
I have some new news on this mod.
First off - I modified all the switches on my panel. When I tested it, 3 of the switches showed they were stuck closed - two of the pinball flippers and the Shazaaam! Button (which are all vertical). I pulled the wires to the switches, and when I pulled the lid of the panel up to pull the wires I noticed that the 6 button (Coin 2) came on. I took this switch out and when I popped the cover off, the spring and sliding contact piece came out, so I think the switch may not have been properly re-assembled to begin with. Oddly, I did not remove the remaining switches, but simply plugged the wires back in and they were working fine afterwards.
Based on the above and some other results that I will get to later, I am downgrading this mod to “not ready for commercial use” (especially with the Happ-Cherry microswitches that efjayel posted originally, although these were
not the ones that gave me problems). What I mean by that is, for example, RandyT’s switches are rated for 1,000,000 cycles (I think he said), and he can comfortably ship them across the country and be sure they will work. These switches seem to work fine now, but I’m not counting on 100 games of Tiger-Heli without having to re-adjust them in my own panel, much less shipping them to someone else. It is however a free and fairly simple mod to do and works quite well when done properly (and re-doing the mod or removing it when/if it fails is not a big deal either) - I encourage anyone that doesn’t like the clicking microswitches to at least give it a shot.
Three of the switches on my panel turned out to be the Happ-Cherry-Bent leaf switches that Efjayel described initially. These are similar, but not identical to the Honeywell switches I had. I found them easier to work on than the D44L and D42Y switches, but harder to modify. The switches were identified as KWJA0017 95073301, so possibly we can find some specs on actuation force. Done -
http://www.cherrycorp.com/english/switches/miniature/k.htm - also 75g. Cherry does make a 25g version of these.
Differences - I believe the KWJA’s are a later design. The cover is easier to remove (no faux rivets to destroy or cut off), the top and bottom contact plates are identical, and all the pieces are firmly retained in the plastic. The D44L and D42Y switches contact plates wobble a bit until the two halves are clicked together. Also, the contacts themselves are centered on the KWJA’s and offset toward the outer cover on the D4 switches. The D4 pivoting contact tends to torque and twist a bit as it actuates, but the coil spring gives it a much stronger “snap” as it pivots down.
KWJA modification: These switches cannot be modified with the same paper that was used for the D4 switches. What you want is a piece of 0.62x0.4 (not 0.5) paper folded tightly in half. This sits in the valley of the bent spring actuator. I tried this on one switch and got the switch to read open, briefly closed as the actuator was pressed, and then open again as the actuator was fully depressed. This might explain Patrick’s missed shots if he was using these switches. The solution for these switches is to move the paper further away from the contacts. You want it back by the vertical section of the COM terminal, not wedged against the right side near the NO and NC terminals like you would on the D4 switches. Even with that, I usually would get a switch that read stuck closed, but I could take a jeweler’s screwdriver and push up on the contact arm toward the NC contact and that would usually get the switch working fine. However, with the D4 switches, I usually had a visual gap of at least a mm between the arm and the NO contact
AFTER the paper was installed. With the KWJA’s, I could just barely make out any gap or sometimes could not even make out a gap. It seemed to work fine on the multi-meter, but it doesn’t give me a warm fuzzy on the longevity of the mod’s success.
D4 Modification: About the only thing I learned is the switches can be finicky about the thickness of the paper used. The paper seems to vary, thinnest to thickest as follows:
Tight fold, inserted crease first.
Loose fold, inserted crease first
Tight fold, inserted crease out
Loose fold, inserted crease out
Having the paper too thick results in the switch either stuck or sticking closed, too thin results in louder clicking (but still much quieter than unmodified). I modded about 3/4ths of the switches loose fold, crease first, before I discovered this, and I
DID NOT go back and re-do them.
Theory and talking points:
I don’t understand
WHY the mod works. Most of the noise to me seems to come from the switch hammering down, with a slight click when the switch is released. This mod looks like it should quiet the release and not do much at all about the downstroke click, yet it works very well.
Hair-Trigger - On both the modded and non-modded D4’s, I did not have a digital scale, but using a multimeter, I was virtually unable to depress the plunger on the switch at all before the switch clicked down and registered closed. With the plunger springs in the buttons removed, the button plunger literally rests on the switch plunger. I don’t see how you could get faster actuation than that - granted, you don’t get a positive return as you would with the springs, but …
Feel - Again, I didn’t have a scale, but the mod significantly changes the feel of the D4 switches. With the unmodified switches, there is moderate initial pressure, then as the coil spring snaps the swing arm down, the pressure is less as you continue to depress the switch, and as you release the switch, the pressure gradually increases until the switch snaps up, and then the pressure tapers back down. With the modified switches, I don’t notice any change in resistance as the switch is pressed and released.