Pinball Peers,
Today I want to call your attention to an upgraded version of my daughterboard combining the functionality of my original daughterboard and new functionality that monitors the health of the Power Driver Board's 5 volt circuit. The new version (which I call the "Pro" daughterboard) has the additional capability of monitoring the original PDB 5 volt line for under-voltage conditions that "would have" triggered an MPU reset had the daughterboard not been installed. A green LED will illuminate at power-up and remain lit until an under-voltage is detected. Upon sensing an under-voltage the daughterboard switches off the green LED and illuminates a red LED. The daughterboard latches on the under-voltage detection meaning it will continue to light the red LED indefinitely until cleared by a three-second power off.
When I released the original daughterboard in February, 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. As I hinted in the CreditDotPinball article, I took that concern seriously. Now the Pro version reveals this “lost” data point.
The Pro Daughterboard is only $10 more expensive than the Classic and of course the Classic Daughterboard will continue to be available for those not wanting the additional capability.
I still like my daughterboard designs because:
(1) It is a plug-and-play installation and the installation is completely reversible. No soldering and no wire or trace cutting is required to install the daughterboard so it can be removed from your machine as quickly as it can be installed.
(2) The watchdog circuit remains fully functional monitoring the power on the MPU board where the most sensitive chips (processor, ASIC, game roms) are located. But off-MPU hiccups no longer cascade into the MPU to trigger watchdog resets.
(3) The resultant redistribution of power loads is an improved balance across the available supplies compared to the factory design.
You can find detailed technical descriptions of my daughterboard on my KAHR.US Circuits website at http://www.kahr.us . You can buy one through my website or through eBay.
As always, my dautherboard solution is not intended to substitute for maintaining the power supply circuitry in WPC systems, but it does eliminate the need to fret over every hundredth of a volt.
Thanks for taking the time to take a look.
-Rob
-visit http://www.kahr.us to get my daughterboard that helps fix WPC pinball resets