Micronics Caslon II 600W PSU Review: A Low-Cost Gem?

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Teardown & Component Analysis

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General Data
Manufacturer (OEM)High Power
Primary Side
Transient Filter4x Y caps, 3x X caps, 2x CM chokes, 1x MOV, 1x CMD0X
Inrush ProtectionNTC thermistor
Bridge Rectifier(s)1x GBU1006 (600V, 10A @ 100°C)
APFC MOSFETs2x Infineon IPA60R190P6 (650V, 12.7A @ 100°C, 0.19Ω)
APFC Boost Diode1x BYC10-600 (600V, 10A @ 78°C)
Hold-up Cap(s)1x Teapo (400V, 560uF, 3000h @ 105°C, LM)
Main Switchers2x MagnaChip MDP18N50B (500V, 11A @ 100°C, 0.27Ω)
Combo APFC/PWM ControllerChampion CM6805 & CM03X Green PFC controller
TopologyPrimary side: Double bridge Secondary side: Non synchronous (passive) rectification & group regulation scheme
Secondary Side
+12V Rectifiers4x PFR30L60CT (60V, 30A @ 50% duty cycle)
5V & 3.3V2x Mospec S40D45 (45V, 40A @ 100°C)
Filtering CapacitorsElectrolytics: Teapo (3000 @ 105°C, SC)
Zero Wattage ControllerMicronics HM-STB01
Supervisor ICGrenergy GR8313 (OVP, UVP, SCP, PG)
Fan ModelGlobe Fan S1202512L (120mm, 12V, 0.18A, Fluid dynamic bearing)
5VSB Circuit
Standby PWM ControllerPower Integrations TNY278PN

This PSU is made by High Power, though Micronics seems to have played a role as well since it provides the zero-wattage controller that allows the fan to spin even after shutting down.

The platform is old. It features a group regulated scheme on its secondary side, along with passive rectification. By today's standards, this is a weird combination, especially since some similarly-priced PSUs come equipped with DC-DC converters for generating the minor rails. A group regulation scheme means that the PSU's performance with unbalanced loads on its rails will be terrible.

Teapo SC caps are used on the secondary side. They're not among our favorites. However, they're still of higher quality than some of the Chinese stuff other OEMs use in their budget-oriented models. The Teapo bulk cap has a long lifetime rating, and it's nice to see a true FDB fan at this price range.

These photos show the PSU's major parts.

Here is the fan's fluid dynamic bearing. Inside, you can see the spiral grooves characteristic of this bearing type.

Our first sample died during the over-power protection test. Its bridge rectifier was fried, and a resistor close to the primary FETs exploded.

The following video shows the Caslon II’s internals.

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Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • nobspls
    Why would anyone choose this one say over the Corsair CX650M? Which you can get typically for $50.
  • Aris_Mp
    Personally I would also take the CX650M in any day of the week, for $50.
  • spentshells
    " Not only does this minimize your carbon footprint"

    The idea of conserving electricity is a fallacy, if you use less the people selling can sell more to someone else..... they aren't just holding on to the energy you saved because you're a hero saving the world.

    Making your footprint smaller doesn't matter in the least when someone else's foot print just gets that much bigger.

    Save some money, sure but for how long? The less you use the more they can charge for that smaller amount later on..... that's how it is.

    On a different note, Ill likely try the psu out at one point on a build for someone else.
  • rohs42
    > The idea of conserving electricity is a fallacy

    No it isn't. Of course a 100 megawatt generator will not be turned off if someone saves 10 watts of power. But if a 10 million people save 10 watts of power, then of course it will be turned off. And if 100 million people save 10 watts, then there'll be no business case for that new gigawatt power plant.

    As citizens, consumers and voters we all bear a small share of responsibility for the state of the world, and we all have a small part to play in making it better. It's only through working together that humanity improves. Your appeal to helplessness and apathy is pathetic.
  • jabliese
    Hey Tom's,

    Once upon a time, we had an extensive brown out at work, which went on for 3 days. On day 2, I was surprised to find many of the PC's that were still working were on 60v power. Over the years, it did not seem to have a adverse affect on any of the power supplies. Lately, I have been wondering what their efficiency numbers looked like during that time, any chance you could add a severe undervolt test to the power supply suite?
  • Aris_Mp
    60V is too low. Most PSUs won't even work at such low voltage. I am surprised to hear that the PSUs at your work were working under such conditions for days.

    Efficiency drops along with voltage input. I want to add more protection tests, however I already have enough fails with the current ones. Nonetheless, I am keeping every suggestion under consideration.