This is another chapter in the ongoing saga of the Sega Mega Drive 32X on PAL hardware.

For convenience, the original problem video is below as well.

After testing multiple 32X units, grounding theories and all sorts of other possibilities, the actual answer turned out to be documented by Sega itself.

Certain PAL and Asian Model 1 VA4 Mega Drives have clock-signal problems when used with the 32X.

Sega identified both EDCLK and VCLK issues.

The EDCLK fault is especially interesting because the signal can become increasingly unstable as the Mega Drive warms up. The 32X-rendered portion of the image begins to jitter and the system can eventually lock up.

That is an extremely good match for what I had been seeing.

Sega’s service fix modifies the Mega Drive motherboard, not the 32X.

So the simplest alternative remains:

Don’t use an affected VA4 Mega Drive with the 32X.

Entirely up to you!

For anyone who actually wants to repair the board properly, the documented service modifications are linked below.

Sources