KAHR.US Circuits

“Great Pinball stuff I invented... and am willing to share”

» Back to KAHR.US Circuits home

KAHR.US Circuits

WPC Power Fix Daughterboard

Item description

This is the WPC Power Fix Daughterboard I invented to help correct resets in WPC era pinball machines.

The 2016 edition of the Classic offers the same, simple functionality as the original design with the regulator updated for efficiency. 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 and 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). The WPC Power Fix eliminates watchdog resets by moving the MPU load off the 5 volt line to the 12 volt line. This reliably satisfies the watchdog circuit and therefore the MPU board is not reset.

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.

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.

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.

Item photos

Kahr website graphics (resized).jpg
PowerFix Gobo for Pinside (resized).jpg

Photos not showing? Make sure your ad blocker plugin is not hiding them.

Order now!

Pick a variation

Classic In stock

$ 29.00

Pro In stock

$ 39.00


From $ 29.00

Price depends on selected item variation.

Ships for $ 3.50 (International $ 33.00)


Contact KAHR.US Circuits (via PinsideMail)

Linked to games

This ad is linked to 47 games:

Other items in this category