I'm glad that you haven't experienced any further problems with your Dreamcast. It could be that adjusting the pins and Power Supply Unit helped out.
OG_DreamcastGuy wrote:My Dreamcast sits inside a TV unit, with enough head room to open the lid but there’s games to the left of the unit and the fan outlet on the right is an inch or two away from the inner wall of the unit. Does this sound like overheating?
However, reading this, I believe it would be wise to take a "belt and suspenders" approach to the issue and potential future issue(s). It might have just been a slight disconnect of the pins or such from the PSU. However the Dreamcast, its CPU, its GPU, and/or its PSU might have overheated from work and where it was situated. The more ventilation and heat removal for them, the better. After all, the Dreamcast is a video game console, but people have to remember that that means it is an application-specific computer. Therefore it should be treated and maintained like a computer.
Dreamcasts, like all electronics, prefer open, cool, dry places. Is there somewhere cooler or better ventilated near your television where you can situate the Dreamcast? After all, all good Dreamcast owners want their hardware and software to last as long as possible, and a few precautions can go a long way toward that goal.