Contents
Excel ATX-400
Excel is a brand I’ve run into a few times over the years, and are among the most gutless units available here. Between my past experiences with Excel, and this unit’s weight (or rather, the sheer lack thereof), I expect this unit to win another fail award.
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And again, it looks like we’re dealing with an obsolete design, with the 5V rail being rated for more than double the current of the 12V rail.
Load Testing
Test 1 (113.56W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 4.75A | 11.87V | 56.2mV |
| 5V | 4.94A | 4.94V | 65.4mV |
| 3.3V | 9.97A | 3.29V | 62.6mV |
| −12V | 0A | −11.69V | 28.8mV |
| 5Vsb | 0A | 5.04V | 7.0mV |
| AC Power | 144.72 | ||
| Efficiency | 78.47% | ||
| Power Factor | 0.62 | ||
Test 2 (192.36W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 9.49A | 11.86V | 88.8mV |
| 5V | 9.76A | 4.88V | 62.0mV |
| 3.3V | 9.88A | 3.26V | 50.2mV |
| −12V | 0.1A | −12.03V | 71.4mV |
| 5Vsb | 1.0A | 5.0V | 11.6mV |
| AC Power | 258.53W | ||
| Efficiency | 74.41% | ||
| Power Factor | 0.58 | ||
Test 3 (243.4W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 13.97A | 11.64V | 105.2mV |
| 5V | 9.86A | 4.93V | 87.6mV |
| 3.3V | 9.88A | 3.26V | 47.4mV |
| −12V | 0.1A | −12.47V | 92.8mV |
| 5Vsb | 1.0A | 5.0V | 10.4mV |
| AC Power | 350.2W | ||
| Efficiency | 69.50% | ||
| Power Factor | 0.58 | ||
As I suspected, the performance was not acceptable, since I couldn’t pull anything at all from it with the ripple in spec. The 5V rail was the main offender, never getting below 62mV. If a power supply can’t deliver anything with all of the rails in spec (both voltage and ripple), then all 10 points come off the final score, and it gets the fail award. The voltage regulation, on the other hand, wasn’t so bad, with all rails staying within 3% of their nominal values. The efficiency, while somewhat better than the Sun Pro, was still bad, never making it up to 80%. 250W was all I could pull. When I asked for more, it shut down. At least it has working Over Power Protection (OPP).
| Rail | Test 2 (192.36W) | Test 4 (243.4W) |
| 12V |  |
 |
| 5V |  |
 |
| 3.3V |  |
 |
| −12V |  |
 |
| 5Vsb |  |
 |
A Look Inside
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The input filtering is theoretically adequate, with two polyester film caps, two common-mode chokes and three ceramic caps (including the one after the rectifier), but there is a major problem – the capacitors are not safety rated. This means that they are much more likely to fail shorted if there is a power spike, and the 400Vdc polyester caps are likely to deteriorate quickly by internal corona discharge on 230Vac. The switching transistors are MJE13007As, rated at 8A. Like the Sun Pro I just blew up, it has 2A bridge diodes. The primary side capacitors are 330µF parts from Koshin.
There are more corners cut on the secondary side. The 12V rectifier is an STPS10120C Schottky rectifier rated for a pathetic 10A, which means that the 12V rail is only capable of up to 10A in theory, not the 18A claimed by the label. The two other rectifiers are STPS2045CTs, which are rated for 20A. The 5V and 3.3V rails were advertised as being capable of 40A and 28A respectively, but this is impossible with these rectifiers. The capacitors used on the secondary side are all from the dreaded Fuhjyyu – one of the least reliable capacitor brands available. There are also no PI filtering coils, which is why the ripple was high.
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The fan is a sleeve bearing part made by Yate Loon. It wasn’t quite as loud as the Sun Pro, but it was still far from silent. The green tape covering the coils pretty much gives away the OEM – Channel Well
Specifications and Conclusions
| Real Wattage | 0W |
| OEM | Channel Well (CWT) |
| PFC | None |
| Price | Unknown |
| ATX Connector type | 20+4 pin |
| Worst-case voltage regulation (12v, 5v, 3.3v) | 2.8%, 2.4%, 1.2% |
| Worst-case ripple (12v, 5v, 3.3v) | 105.2mV, 87.6mV, 62.6mV |
| Worst-case efficiency | 69.5% |
| Input filtering | Adequate – but not safety rated |
| CPU Connector | ATX12v (4 pin) |
| PCIe Connectors | None |
| Molex (Peripheral) Connectors | 4 |
| FDD Power connectors | 2 |
| SATA Power connectors | None |
Pros: Working OPP, Reasonable voltage regulation
Cons: Can’t deliver anything with the ripple in spec, Shuts off above 250W, Inefficient, No SATA connectors, Noisy, Low quality capacitors, Input filtering capacitors not safety rated
Score: 0/10
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