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

Teardown & Component Analysis

Before proceeding with this page we strongly encourage you to a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss.

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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