Any suggestion is better than going blind. I'll try to adjust it in the evening after work.
Anyway a question about adjusting the potentiometers. In the image from this site.
https://www.retrosix.wiki/laser-tuning-pc-engine-duo
I assume this is set near the middle. Just turned a little bit counter-clockwise.
What should be a sensible range of adjustment? What I have been doing when adjusting is from the "middle" , turn the dial 5 degrees counterclockwise, then power on. If nothing changes, do it again, up to 45 degrees. Then reset it to the middle. Then go clockwise then.