There are probably 50 different factors that could go into this answer. But speaking generally...

Yes, I think there is a good chance your pin will not reboot for a good long time.

An independent review says yes: https://creditdotpinball.com/2014/04/25/tech-wpc-resets-the-bane-of-our-existance/

The replacement adjustable regulator for the power driver board is the better choice.

No, you should fix the board right. The Kahr board may last as long as the game, it's well designed. But it's still a patch covering up a problem. It's no different than when someone screws a key in as a coil stop, it will work, and work well. It'll last pretty much forever, but it's not really fixed.

Nice product, it works... I have them in my Indiana Jones and I now have a steady 5 volts.

The board does take the load off an already over loaded 5v supply. It is really better for the machine to use the 12v supply.

It’s permanent for doctor who. It works and I haven’t thought about it since. For the purists......have at it and fix whatever you want. I’ll just keep on keepnnn on...........Playin that is.

It is rock solid, for sure. You will hear arguments that you should fix your board “properly”, but the bottom line is you can leave that thing in there and it will work great forever - as long as nothing else changes. Just remember.. this is Pinball . It can make it hard to figure out what is going on if another problem crops up.

Also if you ever sell, you should think real hard about fixing it properly.

If you are an operator or techician, the answer is no. If you are an enthusiast or hobbyist, the answer is yes. It is based on loading. Some games are worse than others, which makes it even more critical to properly rebuild the board. It is called "bulletproofing" as it eliminates problems from the equation.

Consider the difference between routed games and home use. The Kahr board had home use based on design concept. Operators rebuild or replace boards for full reliability and extended hours.

A comparison would joining wires, electrical tape versus a western union splice, solder, and shrink wrap tubing. Which is more correct and long term although they both work?

Keep flipping.

*looks at thread title*

NO. It is not a permanent solution. I had a random reset problem on my TAF that took me a PCS, 1 in town move, 1 divorce, and a deed in lieu of foreclosure before I got it (July 2016 to March 2018). I went through Pinwikis "reset issue" list line for line. I finally got it by replacing all the ribbon cables, the MPU board, and an aftermarket DMD controller board all at once as I had done everything....and I mean EVERYTHING else. And my game had one of these daughterboards in it.

It is a bandaid. A very well made, thought through bandaid. And i mean that in a complimentary manner, but my game was to the point it did not help it, and sooner or later, everyone who installs one and ignores the problem will be where I was.

Do it right. If you know the problem is isolated to a board, pull the board, send it to someone here that does solid work, wait 1 week to 2 months, suck it up and play your other games. When you get your board back, you know it is sound, and that is a great peace of mind!

*just saw that it is a location game*

That's even more of a reason to fix it. When I find a location game with a reset issue, that is a one and done for me. You don't want your games getting that reputation.

Not the best comparison IMO. Electrical tape is objectively worse than a nice splice with shrink tubing as you describe.

On the other hand, since the original Williams design of the 5V on WPC is so fragile, even though you could repair it and get it working one day, you could argue Kahr's board is the more solid long term fix.

Over 3 years in my Congo.

They have kept a few of my games going well on location for long hours and long time periods so far.

Not permanent. I added one and it fixed resets, later added a color DMD and now get them occasionally during long sessions. The power section definitely still needs attention.

Not a permanent solution. I've had 2 machines with the daughterboard that eventually started failing again, the solution was a proper rebuild of the power board (and the fliptronics board for good measure).

If you don't have the consider confidence and tools to do the rebuild, then the daughterboard is a great temporary solution tho.

Short answer: It’s a patch, but it’s a permanent fix. At least in my experience.

It’s fixed about 4-5 of my games now.

It's a patch, and if you aren't good at boardwork, could be cheaper than having the boards repaired. But if you can do your own boardwork, it's a lot cheaper to fix the 5v issue.

Here is the one I am referring to and it has a tiny pot for adjustment. 5volts can be adjusted to between 5v to 5.20v easily. https://www.ezsbc.com/index.php/featured-products-list-home-page/psu5.html#.WsYSdP6Ww5g

This can be a challenging upgrade, as you have to be super careful with your board (I upgraded one on a DW in which the nuts were completely soldered over) but it is SO worth it. Rock-stable 5v after that

Mike,

I first was alerted to your post late yesterday but watched from the sidelines to let others chime in, but now I'll offer a few thoughts... If you haven't already done so, I'd recommend a review of the technical details on my website: http://www.kahr.us/index2.html . Note in particular the last sentence in the summary section that includes: "The power supplies still need to be maintained..."

To start, the WPC Power Fix is a permanent fix. But remember, my Daughterboard isn't called the "reset fix", so it is most decidedly not a permanent fix for the reset symptom experienced in WPC era games. When installed, it realizes an improved balance of power consumption loads across two of the available power supplies (the 12v regulated and the 5v) and, as long as the Daughterboard remains installed your machine will operate in this improved state. The rebalaning of the loads is necessary because the original designers did not optimally distribute the loads across these supplies - the 5v supply is very heavily loaded in WPC while the 12v digital is minimally used.

The reset symptom is caused when the MPU is starved of voltage because an undervoltage sensor triggers an MPU shutdown. In the machine's original configuration with a heavily loaded 5 volt supply, the resulting reduction in load brought about by MPU shutdown typically allows the 5v supply to sufficiently recover such that the undervoltage sensor releases the shutdown trigger and the MPU boots up again. So, the reset is a combination of two events - a shutdown and a subsequent booting. If the 5 volt does not recover the MPU will not boot and the machine will stay in a shutdown state.

When you install the Daughterboard (or the PSU5, or a computer's supply, or the resistor hack, whatever) that undervoltage sensor is still on your MPU monitoring the available voltage level and ready to shut down the MPU if the supply falls low. In the case of the Daughterboard solution, if your 12v digital supply were to be unable to deliver power the game would shut down. So why does the Daughterboard so consistently eliminate the reset symptom? This brings up the concept of "headroom" with the supplies. The 12v digital is derived from the 18 volt supply. The stepdown from 18v to 12v seems to offer 6 volts of headroom before the 12v would drop from lack of power upstream. I say "seems to" because the math is not quite that simple thanks to the built-in voltage drop in the LM7812 that regulates the 12v and the two worthless diodes upstream of the LM7812, but for argument's sake a 33% headroom offers a robust buffer to fluctuations. Next, in the Daughterboard we are deriving a unique 5 volt supply for the MPU from the 12 v digital. As with the 18 to 12, there is a lot of headroom between the 12 to 5 that gives significant buffer to fluctuations. So, the net effect is a very stable supply for the MPU derived from an under-used supply that is built with a lot of margin for imperfection.

Comparatively the PDB 5v supply construction has very little headroom to accommodate imperfection. The designers could cold have specified transformers with a couple more windings on the 5 volt's secondary connection. That would have raised the upstream side of the LM323 slightly and offered additional error tolerance. But, that comes with a tradeoff because the LM323 is a linear regulator so it would have likely needed a larger heat sink to operate with the higher source voltage and it's already hot in the backbox so you really want to minimize waste heat. Anything you do to the LM323 (hack it, replace it, etc.) has to live within the boundaries created by what the WPC design offers that LM323. So, there just isn't a lot of room to correct for error... and error invariably is introduced as the power supplies age (meaning the typical problems in these supplies - capacitors, connectors, and such).

So, no matter what you do to your machine you are going to need to maintain your power supplies eventually. If you continue to drive your MPU via the original PDB 5 volt supply (modified or unmodified) you are going to need to keep your supply in a very healthy state - like 95%+ of original capacity to keep the reset symptom at bay. With my Daugherboard installed there is a lot more tolerance for imperfections in the supplies... and that can translate into much longer cycles before you have to revisit power supply maintenance. This is what drives the second half of that last sentence I referenced at the beginning of this writeup: "...but no longer do we need to fret over every hundredth of a volt."

The Daughterboard should be in every WPC machine. Can't close without a sales pitch, right? Come get yours at Allentown next month!

-Rob
-visit http://www.kahr.us to get my daugtherboard that helps fix WPC pinball resets or for my new Skee Display Board Set

Convinced me that I need to buy a few more

J210 on the MPU, right?

I had a picture of the board in my WCS'94 lying around. I'm assuming WPC and WPC-S MPU boards aren't much different from each other.

Fliptronics board should be in the upper left of the backbox, MPU board should be on the left side below it.

28157510_228322514402480_8072223129675497472_n (resized).jpg

I have these in a few machines and they are fantastic. Great product from a great Pinsider!

I had one burn up.

This looks like a great add on....Im wondering if I should get one for my TZ?

As a quick fix, yes.

In the long term, no.

You will be disappointed after enough time passes. Just a matter of time. Fix the original source of the problem.

Well as a very part time operator the board is great as my onsite Safecracker is now back in business after continually resetting on bootup. I haven’t really got much time to spend taking the whole board out to get repaired so it’s an awesome solution to get it playable again. I’ve ordered 3 more as insurance policies (had to take this one out of a machine at home). I’ll get the boards repaired one day but for now it’s great.
Rob was also super helpful with postage to Australia.
PS I guess this white stuff on the caps is why I’m getting resets??

09B3CE0A-3B66-4182-9739-5FA1302286D5 (resized).jpeg

Any capacitor that has leaked is almost certainly out of spec. You would have to test it to see how far out but it's cheaper just to replace it.

I've had one in my congo for over 4 years

Congrats on not maintaining your game.

I am not an expert by any means, but everyone is saying this is a game maintenance issue. Is the low voltage at the 5v always an issue with the game? I figured that a lot of these reset issues were from having too many games powered up and running on the same circuit and thus the actual source was not able to supply the 5v, causing the reset.

It's not doing any damage so what's the issue?

Your 1 year on the site I'd like to see you maintain a large collection and host league and tournaments.

Walk before you run.

The low 5v is from components on the boards failing. So the piggyback borrows 5v from a higher voltage supply that doesnt need it. Therefore bypassing a design flaw.

Rob is such a good guy. But I still don't understand his answers.....just know it works.

I've used them reliably to clear the resets - but agree ultimately just get the board fixed.

The voltage monitoring circuit was intended to not allow the machine to fully boot if the 5v went out of spec.. which is a good thing. Other manufacturers did this -- Gottlieb Sys3 MPUs being one that also has issues like this because of components aging. It's like caps going on a sound board because they dry out and audio getting fuzzy or dying completely. Was that a design flaw of the original sound board circuit? Nope. It's electronics aging over time, mostly capacitors, but sometimes a few other components as well that go out of spec. The electronics then need attention. The sound board worked great when it was new.. and for many years after that.

That just looks like the remains of the warranty stickers.

You're arguing it's good that you get a warning- the warning being resets that interrupt the game and sometimes make it unplayable.

Another point of view is it's good to be able to play the game longer before having to address the problem.

Is there any data that shows using a Kahr board is detrimental in any way?

I've had the reset boards installed in all of my WPC games, on route, for at least the last 6-8 years ( I even use them in a few games that have aftermarket boards in them). None of my games have exploded, caught on fire, or otherwise just dropped dead.
The boards ARE a fix. They are NOT a repair.
If you are capable of repairing your entire 5v section, great, it is cheaper than a $30 board.
If you are not capable of repairing your own 5v section, great, it's cheaper than paying someone who can, or replacing the board.
Well that's my two cents anyway...

I like the Kahr boards, but the resets do sometimes return. In my experience, this is usually because a bridge and/or cap goes bad. My suggestion would be to check the bridges with a meter and visually inspect the caps for leakage or bulging. If the bridges & caps are fine, then the Kahr board is the way to go since it's really no different than replacing the 5V regulator with an EZSBC one but much less time & effort. If a bridge or cap needs work, then it's better to replace the faulty components as well as the 12V & 5V regulators with EZSBC since you have to remove the PDB anyway.

It’s great until your components in charge of the 12v circuit begin to show their age.

No one said it's detrimental, even the maker says it's a temp fix on his site. A failing ps will get worse and the fix will stop working.
Right from his site:
The power supplies still need to be maintained, but no longer do we need to fret over every hundredth of a volt.

I've been here far longer than that and have more games then most people here. The board is excellent, it's a patch though. Use it, I do, it works well, c then fix the game and remove it and save it for the next time you need it.

I've had one installed for 4+ years now and no issues. Sorry but its a cheap fix and works! If it one day fails, I'll replace the board, until then for $40 its a great fix.