Appears from pictures on the website write-up that it's based on the ezsbc.com 5v switch-mode regulator and puts that onto a plug-and-play board to get the regulator across the power lines. Neat idea to solve an issue and make it accessible to everyone by having it easy to install/remove. As others have mentioned, it could be even just be used to diagnose a reset circuit is at fault even if you aren't going to leave it in there long-term. I may have to pick one up sometime just for that purpose as I have at least one WPC game on the project list that isn't booting correctly.

That switch-mode regulator that takes the place of a 7812 is pretty cool in and of itself, seems like there'd be a lot of uses in pinball/arcade mods and such with it not requiring a heatsink. Neat stuff.

I'd love to have the appeal this is getting on some of the products I've released, it's always humbling to see a "product mash-up" if you want to call it that, that takes one or more existing products and makes it plug-and-play or otherwise more accessible to the end-user -- especially when it becomes an instant hit. LED strips being offered as ready-to-go kits, this daughterboard idea that takes a 12v regulator and makes it an easy plug-in solution, holiday ornaments with leds and plug-in connectors added to create mods. When you're creating products, this is the type of thing that you hope happens rather quickly and makes it all worthwhile. Congrats on finding a unique twist on an idea and having it be well received!

I'd think assembly goes fairly quick -- couple .156 connectors and the switching regulator, and on top of that, some pins removed from the connectors to make for even less solder points. Probably could get to around 15 assembled per hour, maybe slightly more. Of course then there's testing, but even that would go fairly quick, put it in the machine that doesn't boot up and see that it boots up. When you do a kit there's less of a margin there and now you're making a couple dollars on just the parts/boards and have a lot more time going into shipping, fielding customer questions on the builds, etc. Makes far more sense for PCBs that have dozens of components or hundreds of solder points. Kits take a separate set of instructions, puts "unknown" soldering jobs out there with your name on the boards, time counting out parts into bags, etc. When there's not a lot of components, it's often just easier to offer fully assembled. That said, people do like kits.. so it's nice if things can be offered that way.. but from a business perspective, it doesn't always make sense when assembly time isn't too bad.

Anyone have an issue when turning the machine off where the knocker partially fires? I have tried a similar fix (supplying the watchdog IC with a clean 5v) and have my knocker partially fire on a Doctor Who pinball when turning the machine off. Happens maybe half the time.. haven't tested with and without the voltage regulator in there to attribute entirely to the alternate voltage regulator supplying the watchdog, but so far in limited tests I haven't had the knocker fire when the alternate regulator is not in there.

Just for anyone's curiousity, Leon actually had a similar solution about 5 years ago (labeled his 2nd solution to WPC reset fixes). His first was putting a very large capacitor between 5v and GND going to the WPC MPU. The 2nd solution involving a voltage regulator supplying the watchdog monitored voltage with a clean 5v was discussed back in 2009. At the time some of the German pinball members were going to produce a more plug-and-play solution. Someone toward the end of the forum thread linked below had even suggested an in-line plugin solution that sounded like it would connect at the power inputs to the MPU. Ingo had created a board design, but after discussion it appears it was ultimately determined to not be a great solution & Leon was asked to pull the 2nd solution from his website. I had wondered why I never saw that fix before until stumbling across the PDF below. Anyway I do think people should have an idea of possibly problems using a board like this as a long-term fix.. if it works for you great, but at least know that there could be issues if relying on this setup.

PDF for 2nd Leon solution:
http://www.flippermarkt.de/community/howto/cms/media/pages/pdfs/kompendium/spezielle/Fehler_WPC_Leon_2.pdf

Some links here on discussion & 2nd Leon solution here:
http://translate.google.com/translate?hl=en&sl=de&u=http://www.flippermarkt.de/community/forum/showthread.php%3Ft%3D77389%26highlight%3Dquick%2Bdirty&prev=/search%3Fq%3Dhttp://www.flippermarkt.de/community/forum/showthread.php%253Ft%253D77389%2526highlight%253Dquick%252Bdirty%26biw%3D1280%26bih%3D900

http://translate.google.com/translate?hl=en&sl=de&u=http://www.flippermarkt.de/community/howto/cms/pages/kompendium/spezielle-probleme/reset-quick-fix.php&prev=/search%3Fq%3Dhttp://www.flippermarkt.de/community/howto/cms/pages/kompendium/spezielle-probleme/reset-quick-fix.php%26biw%3D1280%26bih%3D900

IMO I think this type of board is better used as a "diagnostic tool" than a fix or long-term solution. I'm not sure if my knocker partially firing on shut-down is any indication of an issue with this type of setup. I'll have to do more testing to determine that.. but I'm definitely interested in hearing if anyone else that has the WPC Reset Fix board installed has experienced any coils partially firing during powering the machine on or off. Just curious.

There's no doubt that this type of mod can resolve many reset issues, the switching regulator reduces heat and is more efficient, load of the 5v/12v supplies is balanced better. It looks like great detail went into testing all of that and it works as it should stopping resets on these machines. But what is the impact of having the watchdog on the WPC MPU monitoring a totally separate power supply? Blanking is based on this alternate power supply & the blanking signal is fed to other boards in the machine. Without the mod, if the 5v linear supply is out of tolerance, coils/lamps/etc wouldn't be allowed to activate. But with this mod, blanking is based off of the alternate supply.. so the other boards get the "everything's A-OK" blanking signal.. but they are being powered off of a possibly failing 5v linear supply. Maintenance of the linear 5v supply is recommended in the product info, how many people are doing that? Probably not very many. Instead they see this mod can fix their resets and otherwise save $100-200 on a service call and they buy it. If resets go away, problem solved..close up the backbox and play pinball.

The question remains, is it really a good idea to recommend this type of board as anything but a diagnostic / troubleshooting tool – or a temporary quick-fix in a pinch? I think this is where the discussion in the forum post I linked had gone & ultimately why Leon's 2nd fix was pulled from his website. It was the holy grail of WPC reset fixes, but could possibly cause issues as the 5v linear regulator degraded and MPU was otherwise sending an “A-OK” blanking signal to the other boards in the machine. The problem is putting the board out there in any form, people will use it to solve all problems and not do the necessary maintenance on the 5v linear supply -- and when things go south, what happens? That may be the scary part of having this as a product that people are relying upon.

It seems like there should also be separate monitoring of the machine generated 5v circuit on this mod & complete shut-down of the alternate switching regulator circuit (or otherwise proper signaling to the MPUs watchdog) if the linear 5v supply is determined out of tolerance. That would keep the blanking working as it should and this could then be a plug-in-and-leave-in mod without worries down the road of what happens as the linear 5v supply gets worse.

Just some thoughts based on the discussion I had seen and my own interpretation. I'd love to know if this is all something not to be concerned about based on the WPC design though.

Yeah, exactly my thoughts. Various people have commented on this thread about how this adapter is intended to be used versus how it's actually going to be used. We know how this adapter is being used by a majority of the 800+ that have been sold. Plug it in and forget about it. You can't control that from happening other than having a fail-safe built in that would monitor and shut down the alternate regulator or pass on the no-go signal if the linear 5v is found very out of tolerance. So by offering this mod without a fail-safe and for people to be using it as the only method of fixing resets, you open yourself to a good amount of liability IMO. Comments of people using this on-location at a pizza shop for instance -- the machine is on 8-10hrs a day or more, no one is going to be checking in the backbox because everything seems to be functioning as it should – until the linear 5v gets too bad for the other boards in the machine to operate properly. So what is the worst-case scenario in the WPC architecture for the other boards to operate off of an unstable 5v with the MPU thinking everything is okay? What damage [if any] could possibly occur as the linear 5v supply goes downhill? I don't know, I'm not an engineer by profession.. that's why I asked if there's someone else more familiar with the WPC architecture that could answer.

In terms of an improved version of this mod, an audible alarm would be slightly better than led indicators and I'd imagine easily triggered from the same setup you're using to drive the led. A nagging sound coming from the machine once it's triggered would be hard to ignore – and then there's no need to open the backbox unless you hear it. Still I think shutting itself down would be most appropriate if there's any chance it could cause damage to anything as the linear 5v supply fails.

To me this is still one of those “you can offer it, but should you” type of things. Even if you offered it ONLY as a diagnostic tool, people would still use it as a permanent solution once they see that their reset issues are fixed. It's unfortunate but it would happen. The only way to control how it gets used is to either not offer it as product in the first place or have the fail-safes built into it. It really sucks as you want to create these products to help people, but also have to be aware of what you're opening yourself up to should something go wrong.

I can see that viewpoint, but the daughterboard could have more lenient monitoring of the linear 5v supply and not affect the end goal to eliminate the much pickier MPU watchdog monitoring going on. At least in this way if the 5v linear supply got very bad, there would be a proper fail-safe. I may have to try playing around with such a circuit myself -- could be a fun project.

Anyway.. best of luck with the new PRO board! I do think it's great to have a solution like this out there so people have it as a way to aid in diagnosing reset issues. The led indicator is definitely a step in the right direction!

What about the scenario of the machine's 5v supply failing further and the daughterboard still providing the MPU with a solid 5v [separate supply] off of the 12v line? Has that ever been tested to see what the behavior of the other boards / components are since they'd be functioning off of the "failing" 5v line from the power supply?

Okay, I understand the difference between the Classic and Pro.. just was curious of any updates on the scenario of the original 5v supply degrading and becoming dodgy with the reset fix board installed. I guess all that is going to get said on that topic is to maintain the machine properly and/or check the led periodically if you have a Pro version. Doesn't really answer the question of that scenario and is essentially putting any issue with the 5v degrading on the user [which is fair to some extent] but it'd be interesting to actually do a real-world test to see what the hardware actually does in that circumstance.

Hmm.. I'd see pulling the fuse as different than a condition where a dodgy 5v still provides the other boards in the machine with some kind of power, say 3-4.5v from the power supply - something that would still allow some chips on those boards to operate partially, but not completely. Basically what the watchdog would *normally* detect and notify the other boards via the blanking signal to prevent the circuitry on the other boards from trying to "do their thing" without a solid 5v. Only the watchdog isn't aware there's a problem in that case.. because that's the purpose of this reset fix board, to remove the finicky watchdog from looking at the 5v coming from the original supply.

Suppose what you're asking here is if there's any way the voltage regulator would die and short the 12v input to [what should be] +5v output for the MPU. I think most regulators are short-circuit protected and damage mostly occurs from exceeding maximum specs on the input voltage (or applying a negative voltage to the input). So I'd think not, but I'm also not entirely sure of all the ways voltage regulators can fail.

+1. Eventually problems with the linear will come back. Great band-aid as discussed in another recent thread on this board, but several people there had found out it wasn't the long-term fix.

Having an additional watchdog on the plug-in board to handle shutting down the 5v to the other boards via tripping the MPU watchdog when the linear 5v supply gets *too bad* (below 4.0v?) would have been a killer revision IMO. Regardless, if you leave the original caps on that were installed by Williams at the factory.. eventually the linear supplies will degrade.. and problems will be back, or worse.. some stuff could lock-on or get damaged. Who knows. Hopefully those scenarios have been tested for worst-case.

The daughterboard takes 12v input and uses that to give the MPU a solid 5v (via the switching regulator).. so the watchdog on the MPU is looking at this "new" power supply 5v (generated off the 12v linear supply). From the website, it seems the PRO version of the daughterboard would also "monitor" the linear 5v by indicating via an LED if the voltage dropped below a certain threshold. So if the linear 5v gets bad, the CLASSIC would have no indication of this. The PRO would light an led, but that's it. The user would have to be looking inside the backbox to see that an "under voltage" condition occurred on the linear 5v supply. Neither would trigger a watchdog reset on the MPU for the linear 5v being under voltage since the MPU is getting an alternate "5v feed"... and so neither of those shut down the boards if/when the linear 5v gets too bad to run the driver board, DMD, etc circuitry. That's my understanding of it all.