I've ordered one. Would be good to have around for machines that go down at a bad time (league night), and you don't have time to play around with.

I've messaged with Rob for a couple weeks on this, and his logic for using the 12v seems sound. He's done quite a bit of review on the board set.

The root of some people experiencing problems likely rests in determining where the 5v issue is. If the drop lies in the connection between the driver and CPU (most common and easily rectified), then I would not expect much issue. If it lies elsewhere in the driver, and after a while a larger drop occurs, one that normally is never seen as any machine would start resetting by now, I think unknown issues could occur.

I started a new thread "Should the kahr.us daughter boards be a staple in WPC’s?":

https://pinside.com/pinball/forum/topic/should-the-kahrus-daughter-boards-be-a-staple-in-wpc%e2%80%99s

I didn't want to derail this one, but think it's a good question, one I discussed with Rob prior to posting.

I have a low 5v I'm dealing with now which I believe is the regulator, connectors replaced and no drop there, bridges and caps already done a couple years ago, I believe since this started a couple weeks ago it rests in the regulator, so I've ordered the new designed ones that Rob noted in another thread.

The reason I am posting is because I too have experienced a strange thing while finally testing this board. At one point hitting the left ramp caused the diverter to pull back, and drop the ball down the right habitrail, as if for the super skill shot, but it dropped into the auto plunger lane, as the lower diverter did not activate (as it was not time for this to happen), and it sat in the auto shooter lane, and didn’t shoot out. This has never happened before, and happened in the first few games I played with the daughter board. I believe it shot out shortly after, and no other issues, but just odd. I’ve played my TZ to death and never had this react before unless it was for the super skill, and again, this drops into the manual shooter lane always.

Just thought I would report too, as there appear to be small switch things going one with it’s use.

It wasn't like a failing switch issue, the ball went up the left ramp, triggered the switch and opened the diverter, again, as it should for the super skill shot, but didn't activate the other diverter in the shooter lanes, as this wasn't technically the time.

So it wasn’t like a opto going in and out, as the switch is a micro, and the diverter opened once triggered by a micro switch, that had to be physically closed, and did it fast as normally done on the SS shot. Seemed more like a logic hiccup, which never happens otherwise. Anyway, I thought I would report, given other people have noticed similar strange things.

Maybe this is the product of playing a game that has a low enough 5v that it should be resetting anyway, and these little anomalies are being seen for the first time. I’ll look for other issues prior to fixing it for good this weekend when I have time, and report back.

Most resets are connector based. Few are bridges/caps. Many of the unsolvable ones I have found, where 5v has not improved from all the usual fixes, or the 5v is good but still resets, have been attributed to the 5v regulator. In my opinion, this is the single most overlooked failing part in WPC's. All of the issues a couple years back where I had troubles like the above, that didn't fall under the usual reset suspects, I swapped the regulator, and this eventually fixed it.

I read eventually they are something like a 10% +/- in either direction for a true 5v. This means you could have a new one, brand new, new part of NOS, and it could potentially be one on the low end, and not capable of providing enough 5v for a WPC to run. I question that Williams must have known this and tested these prior to installing, as I have not read of a lot of resets for NIB b/w machines.

Early on when repairing my TZ, I didn't know this. Swapped a LM323 in, still low 5, assumed it was something else. It was only when I found out about these switching regulators, and how they output exactly 5v, did I readdress some of these oddball scenarios, which has fixed each issue.

At this point of the game, when a reset falls into the category of not a connector drop and the test point 5v is low, I immediately swap the 5v regulator, takes no time, and it has done the trick each time.

I of course use the Kahr board in the interim, but not long term. As I have said from day one, great tool, but I personally do not feel comfortable with it for a permanent fix, or should I better say, I don't feel comfortable knowing there is an unresolved issue. I had raised the point that the board may be a good replacement as a diverter from the overused 5v, but that didn't seem to go over well with many. I still wonder about that.