Quoted from herg:
This ^ was referring to RBION. I finally got a chance to see and tweak a friend's machine. Initially, I did see some patterns that resulted in nasty flicker, and we tracked it down to no-ghosting LEDs. In manual mode, they weren't lighting at all until about 26%, and not smoothly until about 44%. We tried setting B1 for the active profile to 44%, and it did smooth out the flickering pattern, but it also made it difficult to see the intentional blinking. I dropped B1 back down to 30%, and it was a pretty good compromise.
He said he would swap the bulbs out to standard LEDs without the no-ghosting, and I think that will allow us to drop B1 back down to the default 10% and have nice effects all around. We'll have to wait and see.
Just to confirm, the easiest place I could see the flickering pattern was right after the match sequence switched over to attract mode. Here it alternates between X's and diamonds on the 3x3 grid. Is that were you saw the nastiness?
Thanks for taking the time to tinker with this on your friend's machine.
The issue where I am having the strobing problem is indeed on part of the attract mode. For about 1/3 of it, where the game is lighting up every bulb rapidly, that's where I get the bad flicker. Another 1/3 of the attract mode does a basic stepping pattern where it lights random bulbs on 100% solid then 100% off, so no problems there. Likewise, the last 1/3 of the attract mode does a nice wave motion back and forth across the playfield, and it lets the bulbs fade in and out smoothly. Obviously that is fine, since the OCD especially excels in those situations. Keep in mind the part I am having a problem with strobes/flickers intentionally and it does this with standard incandescent bulbs, but with the LEDs I have it's even more noticeable.
I will have to try some CoinTaker Super Brights. That's what I had put in my last three Sterns that had this board. In RBION, I used the same clear-domed, two-LED model that I used for GI. I wanted to see how the lights would work using the same bulbs above and below the playfield, just like with how a game is normally configured using incandescents. It actually looks good for the most part, but I've been meaning to start color matching anyway, so in the process I'll get some Super Bright CT bulbs for the inserts that have an obvious problem (like the tic-tac-toe board, that's the biggest offender in the attract sequence).