SilentiumPC Elementum E1 SI-350 (SPC124) review

Primary side

The primary side starts with an input bridge rectifier, the GBU606. Without a heatsink it can handle 3 A continuously at 600 V and 100 °C, or 175 A peak (for 8.3 ms). The voltage drop is 1 V per diode at 3 A. The PFC choke is smaller but for this amount of power at 230 V it is more than adequate. The PFC transistor is the Silan Microelectronics SVF13N50F (13/52 A at 500 V and 25 °C, RDS(On) 0.52 Ω at 6.5 A and 25°C) in a TO-220F package. The diode is an NXP BYC8-600 (8/60 A at 109 °C and 600 V, drop of 1.85 V at 8 A and 150 °C, 2.9 V at 25 °C) in a TO-220AC package. Both share a common dedicated heatsink.


As for the bulk capacitor charged from the PFC, there is a JunFu HG 180 μF/400 V. I have measured its capacity at 152 μF. This series has a minimum lifetime of 2000 hours at a maximum temperature (105 °C) and ripple, if you’re actually naïve enough to trust their datasheet. The switching transistors it feeds are another two SVF13N50F in a two-transistor forward configuration. They have also their own heatsink. The main transformer has an ERL-28 core.


As for the driving circuitry, there’s the Champion Micro CM6805BSX microchip in a SIP-9 package. It provides a combined control of both the PFC and the switching transistors, with a fixed frequency of 67.5 kHz. Asia’X caps are used to filter its power supply or for feedback. I would say that for a low-end unit at this rated power, this silicon is nicely overspec’d, and for that the unit gets two extra points.

+5 V stand-by rail

The stand-by rail uses a PWM microchip with an integrated transistor, namely the Power Integrations TNY176PN. The transistor’s On resistance is 16 Ω at 25 °C. With a maximum switching frequency of 140 kHz, it can supply up to 19 W in an open-frame design.


An FS5V45 diode is used for single way rectification. I found no datasheet for it but my estimate is 5 A/45 V. A Chemi-Con KY 1000/16 is used for filtering before the Pi coil and an Asia’X TMX 1000/10 after it. It is nice to find a good cap on the stand-by rail in a unit of such a low price.

Pages: 1 2 3 4 5 6 7