Was having "random" reset issues on my ToM machine, and learned that this is a common problem with Williams WPC systems, so I went on eBay and bought the Kahr daughterboard hoping that it would correct my issue. When I went to install it, to my surprise, I FOUND a Kahr board already installed on my machine - the 2017 version. Okay, so apparently that board wasn't fixing the reset issue. Popped the new board in; same story. So, I thought it must be some other, deeper issue I need to solve and just left the daughterboard in place.
My issues got worse over time. Here's what was going on:
Tiger saw motor would come on and stay on after random resets, until I powered down the machine to get it to shut off.
Mirror lights would either come on before everything else, or afterwards - very sporadic.
Trapdoor would randomly pop up, especially during multiball
Theatre Entrance LED strip would only partially light up, and after some time running, the full strip would start working.
Random resets and lockups
Bricking: tried and failed multiple times to power on the machine, which refused to boot up, showing a blank display, no G.I., no nothing except a speaker pop.
Hitting the trunk skillshot would make the entire machine reboot
And finally, while trying to diagnose WTF was happening to my machine, random resets every 10-15 seconds.
Finally, I decided to pop the Kahr board out and plug the original connector directly into the header... And now the machine is running PROBLEM FREE. I don't know why the previous owner had installed this board to begin with, but I've had "random" reset issues since I bought this machine (only a few months ago).
My question is, if your machine DOESN'T actually have an issue with low voltage resets, will installing this board make things worse? Because it sure did with my machine. It's been a total nightmare!