Prevent your WPC machine from resetting by fixing the power loading!

• The WPC Power Fix is designed and made in America (Arizona and Virginia)
• Recently released low quality foreign knock-offs over promise and under-deliver. Choose the original WPC Power Fix!
• Six years of proven performance with over 7,000 delivered
• KAHR.US Circuits recommends TILT Audio for your pinball sound needs
• The C​lassic Daughterboard:  The Pro Daughterboard:

This circuit creates a unique 5 volt power source for the MPU board.  Resets happen on WPC pinball machines because the Driver Board's 5 volt power supply is minimally sized for the many functions it needs to drive.  WPC series MPU Boards have a watchdog circuit that shuts down the board if the voltage on the 5 volt line drops below a cutoff voltage (around 4.7 volts).  When this happens the machine appears to unexpectedly turn off - immediately ending any active games. Interestingly, the watchdog shutting down the MPU board often sufficiently reduces the draw on the 5 volt power supply such that the voltage quickly recovers and the machine starts booting as if all were well once again.  Unfortunately all is not well - in some cases re-energizing the MPU board just as quickly pulls down the 5 volt power supply and the watchdog again turns off the MPU - creating an endless on/off reset cycle about every two seconds.  Even if your machine doesn't enter this rapid "reset loop" but if your machine resets, your machine will experience additional resets - the periodicity of your reset loop may be minutes (or even an hour or more) but you are just waiting for the next reset.  

The WPC MPU Power Fix eliminates watchdog resets by moving the MPU load off the 5 volt line to the 12 volt line.  If you look at the WPC MPU Power Fix board, several pins are missing from the wire-side connector... this is because the Driver Board 5 volt line is no longer passed to the MPU.  Instead a switched regulator generates a very stable 5 volt supply that is used only on the MPU.  This reliably satisfies the watchdog circuit and therefore the MPU board is not reset.   

Other parts of your pinball machine still use the original 5 volt power supply so best maintenance practices such as replacing failed capacitors, burnt connector pins, and non-functioning rectifier diodes still must be performed. At long last, however, you no longer have to worry about every hundredth of a volt when conducting these repairs.

A link to Detailed technical Discussion of the daughterboard in a WPC system

See a replay of my technical seminar from the 2019 Northwest Pinball and Arcade Show - Start at 1 hour, 30 minute mark (UPDATED LINK COMING SOON)

Here is a short video showing the WPC MPU Power Fix solving resets in my Party Zone pinball: WPC MPU Power Fix on YouTube

The Pro daughterboard implements the same reset-preventing solution as the classic daughterboard but also includes additional circuitry to monitor your Power Driver Board.  The 2016 edition monitors the driver board's 5v and 12v supplies!  Simply inspect the LEDs to quickly determine PDB power supply functionality.  New in 2018 includes the 2017 edition's additional indications PLUS a button to restart the monitoring sequence without rebooting the game... How to read the LEDs:

Green LED lit means both your 12v and 5v power supplies are stable Flashing Green LED 5v supply exceeded 5.6v Red LED lit means at some point since turning your machine on the PDB 5v power supply dipped below the voltage that would have triggered a reset had the daughterboard not been present Flashing Red LED means the 5v supply fell very low and needs maintenance Blue LED lit means the 12v supply is weak - at some point since turing your machine on the PDB 12v regulated supply dropped below 9 volts Red and Blue LEDs lit means both supplies on your PDB have triggered alerts.

This monitoring helps you make informed decisions about when to maintain your PDB power supplies.

When I released the original daughterboard, some concerns were raised about the reset being an early indicator for needed power supply maintenance and that by preventing resets the indication is lost. The Pro version reveals this "lost" data point. 

Remember, there still is no magic in my daughterboards - if the 12 volt supply is not sufficiently stable to drive the MPU load, you will see resets (the blue LED on the Pro will help you diagnose this possibility). But with the Pro daughterboard monitoring the PDB power supplies you can now have an enhanced understanding of PDB power supply health.

Should you buy the Classic or the Pro version? The simplest way to decide is to determine whether you would ever open your backbox to read the indicator LEDs on the daughterboard.  

Jimmy in Texas posted this video showing how to install a daughterboard:  https://youtu.be/qVT-iR0JIOA

The WPC MPU Power Fix circuit board is plug compatible with WPC, WPC-S and WPC95 MPU Boards.  Simply unplug the 7-pin power connector from your MPU.  Plug this connector into the WPC MPU Power Fix circuit and then plug the Power Fix circuit into the MPU board. The 2012 design is shown in these pictures, but the current design installs identically.

 Buy the CLASSIC daughterboard here via Paypal with the Add To Cart button for $32.

Shipping is via First Class mail or Priority mail.  

Available on Ebay and through Pinside Shops

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Big Daddy Enterprises also has a supply of CLASSIC daughterboards

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CANADA - Buy the CLASSIC daughterboard from John's Jukes, LTD at www.flippers.com or via the Paypal button to the right.

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EU - Buy the CLASSIC daughterboard from Pinball Heaven - www.pinballheaven.co.uk

Buy the PRO daughterboard here via Paypal with the Add To Cart button for $42.

Shipping is via First Class mail or Priority mail.  

Overseas shipping is via US Post Office Priority Mail International.  Unfortunately for overseas, shipping one costs the same as shipping
18.  If possible try to combine orders with your friends/league/etc.

Now Available at Marco!!!

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EU - Buy a PRO Direct from KAHR.US Circuits for 35 Euro each. Priority Mail shipping is expensive at 30 Euro, but it is flat rate shipping for up to 20 daughterboards!

How to buy with EURO

• Calculate cost for the total order - 42 Euro per Pro plus 30 Euro per order shipping. BULK DISCOUNT: If purchasing 10 or more, use 33 Euro per Pro plus 30 Euro for shipping.
• Transfer Euro for the order to my Transferwise account

  TW Account holder	KAHR.US Circuits
  Bank code (SWIFT / BIC)	TRWIBEB1XXX
  IBAN	BE23 9670 3720 2391
  Address	TransferWise Europe SA Square de Meeûs 38 bte 40 Brussels 1000 Belgium

• Send me an email with your shipping address (rob@kahr.org) and confirmation of quantity ordered

This bundle includes:

1. One WPC Power Fix Pro Daughterboard
2. One 12 Volt Switching Regulator (PSU3-12) to replace your LM7812
3. One 5 Volt Switching Regulator (PSU5) to replace your LM323

Buy via Paypal -  $60

International:  Overseas shipping is via US Post Office Priority Mail International.

International:  Overseas shipping is via US Post Office Priority Mail International.