One of my Model 1 Sega Saturns has developed a rather annoying power supply problem. It becomes more noticeable after the console has been running for a while, so I left it operating for over an hour to get everything thoroughly warmed up. The built-in music player was more than sufficient for that experiment.

Once the problem appeared, I recorded the noise in stereo to help narrow down which component was responsible. It’s the sort of intermittent fault that’s especially annoying because everything can appear perfectly normal when the machine is first switched on.

My suspicions were around the internal power supply. From what I could hear, I wondered whether a transistor, the bridge-rectifier circuitry, or perhaps the transformer was responsible. That’s only speculation at this stage, though. I’m absolutely in no way trained in electronics, and the recordings don’t establish which component is making the noise.

The Saturn’s internal PSU contains mains-voltage circuitry, so this isn’t something to poke around inside while powered unless you’re appropriately qualified. For now, I’m more interested in documenting the behaviour and comparing it with the other Saturns I’ve got available.

I tried compatible power supplies from two of my Model 2 Saturns, and neither reproduced the same problem. That makes the original PSU look rather suspicious, although it doesn’t mean every Model 2 supply is interchangeable with every Model 1. Sega used several arrangements across the motherboard revisions.

I’d quite happily buy another suitable power supply if I could track one down, but they’re becoming harder to find. This is also giving me a good excuse to investigate an alternative using an external DC supply and suitable converters. If I can get that working, perhaps these early Saturns won’t have to rely entirely on their ageing original power supplies.

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