Back from the Grave: Sega Saturn (losing power, flashing LED)

Sega's Saturn holds the unfortunate fate of being the beginning of the end of Sega as a hardware manufacturer.  Launched in 1994, Sega mistakenly believed their competition would come in the form of the (unsuccessful) Atari Jaguar and designed their console primarily as such, essentially pairing two Mega 32X consoles together for a 2D graphics monster with some 3D capability.

Sadly, between developers being unable to fully utilise a twin-CPU, twin-GPU system, and the extremely successful launch of Sony's fully-3D PlayStation, the Saturn would prove to be a financial disaster from which Sega would never fully recover.  It was discontinued in 1998 with just 9.26 million units sold.

This Saturn has belonged to my brother since new, when it was first available for sale locally in 1995.  It saw out the fall of Sega's hardware division with semi-regular usage before finally succumbing to failure within the last 12 months.

As with the Game Gear, the fault we encountered is reportedly common; or at least the symptoms are.  It starts with the system randomly losing power, but eventually finishes with the system unable to maintain power for longer than 30 seconds at a time.  Following each attempted power-up you must then wait before it will even attempt to power on again, else it won't do anything.  Often times the power LED will flash briefly, with a sometimes audible click.

Generally, the advice given is the same: replace the PSU.  This does work, and that the Dreamcast shares the same basic PSU means that there are after-market options available (usually in the form of mini-PC power supplies).  However, it requires minor modification to support the 12VDC jack, plus allowing for an external DC adaptor, in addition to modification of the PSU itself both so that the voltages are correct and so you can even plug it into the console.  Plus it's also an unnecessary expense, usually costing around US$50.

The issue, it seems, is primarily the result of the oscillator chip failing.  This is a TOP201 in the 115V/60Hz systems and a TOP202 in the 230V/50Hz systems.  The 30-second runtime is the default "bootstrap" for the chip, after which it requires feedback from the system in order to continue.  With a failing chip, this feedback rapidly drops, causing it to increase the output voltage until a safety circuit cuts power entirely.  2 minutes are then required for the chip to "reset" itself before it will try again.

Replacing this one chip can be done without specialised equipment - just a small phillips screwdriver and a soldering iron (a sucker or wick may also help but isn't strictly necessary).  It uses a standard 3-leg TO22 package, meaning you simply need to unscrew it from the heat sink and then unsolder the legs.  Installation is the reverse, though given its workload it may not be a terrible idea to use a small amount of thermal paste between the package and the heat sink itself just in case. 

While we were in there, we did also discover a resistor which seemed to have physical damage, in the form of what appeared to be charring.  Since this isn't normal we also replaced it as well, though it may simply have been cosmetic damage (perhaps even from the TOP202 failing).  Total cost of the repair was under AU$4, plus we now have spare TOP202s in case this one fails in another 23 years' time.

So ends this BftG.  Since this same basic setup is still used in the Dreamcast we'll probably have to use this process again in the next few years.  Unfortunately if this isn't the problem it may take some more figuring out, as flyback switch-mode power supplies are relatively complex beasts (we're still struggling with one from an Apple IIe, which will hopefully feature on BftG eventually).

Remember that electricity can be dangerous to both property and life.  If you don't respect it you can wind up seriously hurting or even killing yourself or others, and chances are it's going to be painful while it's happening.  Unless you're sure of what you're doing, avoid tampering with any electrical circuit - especially when it's live or mains powered - and always ensure you have a nearby assistant who can contact emergency services.