How can I fix CRT sync issues on an arcade Raspberry Pi setup?

[Richard.L]

I’ve been trying to get my custom arcade cabinet’s CRT monitor to sync properly with the new Raspberry Pi setup, but the picture keeps rolling or tearing no matter what I adjust in the config files. I’m starting to wonder if the issue is with the sync signal itself, and I’m not sure where to go from here.

[OliverL]

Yep, I chased this for weeks on a 25 year old CRT too. Rolling picture, no matter what I did in config.txt. I finally admitted that the Pi might not be feeding the right timing to that CRT. I swapped to a cheap RCA CRT with a simple scaler box and that stabilized things enough to stop the rolling caused by bad sync. Still not perfect, but it’s usable for retro games.

[Luke57]

I muddled through config options, tried forcing HDMI mode vs composite, tried different cables, checked the ground, and even watched the HDMI clock with a quick scope read in a pinch. Nothing stuck, so I moved to a hardware scaler in front of the CRT and that was the only thing that helped predictably.

[LaylaC]

Do you think the real problem is the timing itself, or is there something else going on like the monitor's own tearing or the cabinet's power supply?

[Benjamin_L]

One thing I kept thinking about but never solved: maybe the signal is fine but my cabinet’s shield or grounding introduced noise; I briefly tried running a separate 5V supply and tying the grounds differently, and it helped a bit but never fixed it.