Page 3 - Physical Look - Inside
After drilling through the warranty seals and several other screws reveals the inside of the Seasonic M12II 500 power supply. The interior design should be quite familiar to most people, since Seasonic OEMs a lot of power supplies. Do keep in mind that the Seasonic M12II is a Tier 1 Seasonic self-branded power supply. As you can see from our photo above, the printed circuit board is significantly smaller than the housing of the unit. As described on the rail configurations on the previous page, changes to the rail configurations are evident, but it still retains the same dual forward converter design.
The construction of the modular cable interface at the back of the power supply is also done very well internally -- the soldering of the traces between the internal contacts and detachable cable connectors, as well as overall construction are built with quality in mind. It's also nice to see that the non-detachable cables are soldered half way into the M12II housing with rubber along the edge of the cable opening.
A shot at the back of the power supply -- the AC power input as well as the on/off switch is located on the other side. A ferrite bead (Black) can be seen above in the main power cable lead-in. As you can see in our photo above, the thin and open honeycomb grille allows tons of air to move freely -- and with no components clogging up the way, heat isn't really trapped to a great extent.
More iron ferrite coils can be seen. The power cables are soldered very cleanly onto the board, it's a good indication of quality as we see quite a bit of power supplies doing a very dirty job in this segment because they expect no one to look in there. The Seasonic M12II has the inside done as well as the outside.
When it comes to capacitors, Seasonic historically focused on using high quality Japanese units -- the Seasonic M12II is no exception. Unlike the Seasonic S12II, which as far as I remember uses a single solid aluminum capacitor as its main capacitor, the Seasonic M12II 500W continues to use electrolyte based units. The biggest change is that every capacitor inside the M12II is now rated at 105c instead of the more common 85c ones -- the array of secondary/output capacitors are Nippon Chemicon electrolyte units, while the main input capacitor is an industrial grade Hitachi capacitor designed for up to 105c as well. When you mention quality, the Seasonic M12II sure fits the bill, and it's especially important when you're spending top dollar for the Seasonic M12II 500W power supply.
With the removal of the rear 60mm fan, Seasonic implemented an extra heatsink for heat dissipation -- up from the standard two. Another prominent change is the size and design of the heatsinks -- these black painted units have shrunk in size, with their teeth also shorter. With more heatsinks and a smaller size each, it should improve airflow inside the power supply as well as more efficiently spread over a larger surface area.
As usual, the Seasonic M12II 500W utilizes an ADDA 120mm fan for cooling -- something that Seasonic has been using for many years. These ball bearing fans are very quiet at low RPMs, but typically has a barely audible 'clicking' sound when running. The Seasonic M12II is no exception, but unless you are sitting 5cm away from the power supply all the time, it shouldn't be a problem at all. These ball bearing fans are generally not very vulnerable to heat, which is important especially when working inside a power supply unit -- not every 120mm case fan can do this. A piece of clear plastic covers a part of the fan to improve better airflow across the power supply. Rubber washers are also placed between the power supply and its attachment to the housing of the power supply to minimize vibrational noise.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion