This is a hook up kit, for Stern SAM-based machines, that does all the hard stuff for you and turns the knocker installation into a twenty minute plug and play experience. I do not supply the knocker itself. You can get them anywhere. For my first test I took the knocker out of my Tommy, haha, and put it in my X-Men. I don't yet supply the Stern 50V step up board but I plan to. They are easy to get anyway, so if I can't organise supply then basically get a knocker unit and step up board from your favourite parts vendor, and this kit, and you'll be good.

The kit consists of two tap PCBs. One for the 50V coil power at J10, and another that combines Q24 and the 20V (required to allow the step up board to work) at J7. I know you can get Q24 at the coin door, but I've done this because it's better. It's cleaner, combining the 20V in the same tap, and if you want to keep your whole knocker setup in the back box then you can.

Here are the taps. The power tap has both pin8 and pin9 on it for two 50V supplies (I use this tap for my drop target power as well). Note that pin8 has a 4A fuse in it on the driver board, so you might want to change that to a 3A to match the fuse used for all the other coils. Both taps are correctly keyed.
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Here is the power tap going into J10.
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Here is the Q24 tap going into J7.
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The cable harness. I have provided plenty of length if you want to mount your knocker in the main cabinet.
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This plugs into the Stern 50V step up..
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This goes back to the 50V tap..
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This goes to the Q24 tap..
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This goes to your knocker coil..
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Put your knocker in..
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Set the knocker settings in your menus and away you go. Note, to test your knocker don't use the Q24 test. Just use the main knocker test. With the knocker volume set to off, it still plays during the test, along with the real knocker, but when you get that first replay, bam, no chirp.

I plan on keeping these in stock at the website (which is now secure(yay!)) https://redshiftled.com.au but right now I only have very limited numbers in stock, due to a few annoying parts shortages. I should have more up within the week. Price is A$50 (about US$38). I won't actually have them activated on the site until tomorrow as it has just gotten too late to do it tonight.

My site is back open as I get on with restocking. Knocker hook up kits are here..

https://redshiftled.com.au/Store.php#!/Knocker-hook-up-kit/p/97163161/category=26351491

My soldering iron broke, so I don't have as many there as I would like, but more will be coming. Remember, currency is A$. These are only about US$38. You need to get the step-up and a knocker. That would be about another $33 from Terry at PBL.

Well, after a miserable wait for customs, my 50v step up boards are out for delivery today. Knocker hook up kits with everything except the knocker assembly are in stock now.

You get..
50V Power tap,
Q24/20V tap,
Stern 50V step up board,
All cabling.

You just need to supply the actual knocker. I use the DE ones from Pinball Life, but you could probably use any knocker assembly. I'm going to try their Spooky one as well..

https://www.pinballlife.com/index.php?p=catalog&mode=search&search_in=all&search_str=knocker

https://redshiftled.com.au/Store.php#!/Hook-up-kits/c/26351491/offset=0&sort=normal

I mounted my Metallica on the floor firing into the forward cabinet brace. I tried the mid brace but it didn't seem to resonate well. It's a really easy access point too.

I haven't tried the sidewalls yet, as there is a corner piece along the edge to reinforce the joint that gets in the way, and the knocker needs to be lifted a bit. Will be interesting to see where the best mounting point is. On the wooden backbox models the sidewall of the head works great!

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I went with 50V as I had already built the 50V tap to use with drop targets. Didn't consider 20v. I may just build my own switch and use the 20V that comes with the Q24 tap, and do away with the need for the stern board. Idea worth checking. Cheers.

I’ve settled on this as the absolute best place to mount the knocker. On the floor, firing against the back wall. Super easy to put in as you can just sit the knocker assembly on the floor to drill, and it is super loud and really rings. Seems like a really resonant part of the cabinet.

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