Quoted from Frax:Here's a crazy question...
Is there a way to make a power (GI on my Space Shuttle comes from power board..) or driver board supply enough constant voltage/amps to the GI circuit so that there is not flicker when you fire up the flippers and other solenoids? Always have wondered if anyone would try to "correct" this in new board designs, or if it's even possible.
The challenge with what your asking is that GI is 5.7Vac (ac voltage) which you get through a multi-tap transformer. Since solenoids are powered through rectified AC with a single big cap, when you fire the, when you fire your solenoids, if the cap is old, it will drag the entire transformer down causing all of the other non regulated voltages to drop slightly. The best thing you could do is replace that big cap on your solenoid bridge.
I looked into converting the GI into DC but that it was an expensive solution. Most GI requires ~20A @ 5.7Vac. The heat generated with the conversion was too great. Most didn't like it.