The PC-Engine DUO line of consoles has an internal memory to store game’s saves. But this memory is not like an SDCard as it needs to be powered in order to retain the data. Unless other systems of the same era, the DUO does not use a coin cell nor a rechargeable NiCD battery. It uses a Super Capacitor. This kind of component last longer (between 10 to 15 years) and has a near infinite number of charge / discharge cycles. However, the self discharge rate is high : about 40% to 50% in one month and it can store less energy than batteries. So if a brand new DUO was probably able to keep saved data for 2 or 3 months while switched off, it may not keeps the data that long after more than 20 years. Fortunately, this super capacitor is very cheap, easy to change and we can even triple it’s capacity !
This is the story of my DUO new super capacitor…
Needed materials
- If I’m not wrong, any PC Engine DUO model, has they all use the same super capacitor
- A soldering Iron
- A super capacitor not taller than 2 cm. The original one is 0.47 Farads, I used an 1.5 Farads one
- A desoldering Pump (optional, but a lot easier)
Removing the original capacitor
The easiest way is to use a desoldering pump to remove all solder and free the holes for the next step.
Putting the new one
The super capacitor I used does not have the same form factor as the original one: it is a lot thinner but also taller. In order to be able to solder it on the back of the motherboard, I first added a little bit of solder on one leg in the front side. Then I soldered it normaly on the back.
Finally, I had to bent the capacitor so the console could be closed correctly.
