The Cirqus Voltaire Eddy Fix
The Cirqus Voltaire eddy board is notorious for missing fast shots to the Ringmaster. It turns out that there is a design issue. The board as designed adds a significant delay to the sensor - about 22 milliseconds. A fast ball travels at about 4 mm/msec, and therefore covers the 25mm path across and back over the sensor in about 6 milliseconds. These fast shots do not register - they are too short for the 22ms filter.
The Quick Fix
There's an easy fix (please note: you perform this modification at your own risk). A single part governs the delay, a capacitor at C3. The part also suppresses spurious readings, but that does not appear to be a problem with the eddy boards. All you have to do is raise the playfield, and use a pair of cutters to snip the leg of C3 at the point identified by the arrow in the picture (click for full size). The board is in the area adjacent to the top left of the Ringmaster mechanism when the playfield is raised. It sits vertically, with C3 at the top left side.
There is one caveat: removing C3 does seem to cause instability in some boards (20% is my guess). The new microcontroller eliminates this problem.
(And thanks to my testers Joe and Theo).
Now, if you really don't want to modify the board, we have exact functional replacements for them at Pinbits and can customize one for you.
The Other Problem
There's another problem. The eddy board occasionally locks up, and the Ringmaster ignores hits until the ball drains and the machine resets the board. The auto eddy board sets the control for the eddy detector very close to the "hot point". So if it drifts, it can lock up. This is not adjustable on the board. The problem also exhibits itself on the right flipper on Monster Bash.
We have a new version of the eddy sensor program completed and tested. The new software takes responsibiity for all calibration and reliability. It tests the controller on a regular basis, and resets itself it detects any problems.
Here's a picture of how the eddy sensor control board is wired.
Note the blue-white wire. It isn't really ground. The power-driver board pulls that line low to enable the eddy controller. To reset it, it lets it go high and then pulls it low again.