Contents
Generic ATX2000
With absolutely no branding on the label, I have no idea who the manufacturer is. Could it be that they don’t want us to know who to complain to if the unit fails? Let’s see.
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5V heavy again.
Load Testing
Test 1 (110.21W Load)
| Rail | Load | Voltage | Ripple |
| 12V | 4.4A | 11.79V | 20.6mV |
| 5V | 4.98A | 4.98V | 28.6mV |
| 3.3V | 10.0A | 3.3V | 31.6mV |
| −12V | 0A | −11.44V | 14.2mV |
| 5Vsb | 0A | 5.01V | 260.0mV |
| AC Power | 145.1W | ||
| Efficiency | 75.95% | ||
| Power Factor | 0.6 | ||
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Test 2 (191.22W Load)
| Rail | Load | Voltage | Ripple |
| 12V | 8.8A | 11.71V | 27.0mV |
| 5V | 9.92A | 4.96V | 32.8mV |
| 3.3V | 9.97A | 3.29V | 29.4mV |
| −12V | 0.1A | −11.84V | 32.2mV |
| 5Vsb | 1A | 5.0V | 15.8mV |
| AC Power | 249.9W | ||
| Efficiency | 76.52% | ||
| Power Factor | 0.58 | ||
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Test 3 (259.26W Load)
| Rail | Load | Voltage | Ripple |
| 12V | 15.1A | 11.26V | 39.2mV |
| 5V | 10.04A | 5.02V | 35.4mV |
| 3.3V | 9.94A | 3.28V | 27.8mV |
| −12V | 0.1A | −12.27V | 41.2mV |
| 5Vsb | 1A | 4.99V | 17.2mV |
| AC Power | 350.3W | ||
| Efficiency | 74.01% | ||
| Power Factor | 0.58 | ||
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Test 4 (307.38W Load)
| Rail | Load | Voltage | Ripple |
| 12V | 20.4A | 10.62V | 55.2mV |
| 5V | 10.2A | 5.1V | 40.8mV |
| 3.3V | 9.91A | 3.27V | 28.4mV |
| −12V | 0.1A | −12.64V | 18.6mV |
| 5Vsb | 1A | 4.99V | 55.6mV |
| AC Power | 447.5W | ||
| Efficiency | 68.69% | ||
| Power Factor | 0.57 | ||
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The 12V Voltage regulation was absolutely appalling. Under 260W Load, the voltage was at 11.26V – below the minimum allowed in ATX specifications. When I asked for about 300W, things got even worse – the 12V rail was then at 10.62V – a whole 11.5% under. That is officially the worst 12V regulation I have ever seen from a power supply. The other rails were OK; the 5V rail gave 2% regulation and 2.8% variation, while the 3.3V rail managed 0.9% regulation.
The efficiency was also very bad, never managing 80%. When I attempted lo load this power supply to 350W, the 12V voltage dropped to about 10V and it continued to drop over the next 30 seconds or so. It got down to about 9.6V, and the PSU then failed. It didn’t explode, but there was smoke coming from the fan grille. It turned out that the main toroid coil had started to burn up. It was noticeably darkened and had much of the insulation melted.
| Rail | Test 3 (259.26W) | Test 4 (307.38W) |
| 12V |  |
 |
| 5V |  |
 |
| 3.3V |  |
 |
| −12V |  |
 |
| 5Vsb |  |
 |
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The ripple suppression was acceptable, but not spectacular. The 12V rail stayed just below half the maximum allowed, while the 5V and 3.3V rails were just above half the maximum. Test 1’s ripple results aren’t shown in the table, but it’s obvious from that test that the 5vsb rail doesn’t like not having a load on it, as the ripple on that rail was at 260mV during that test – over five times the maximum limit. While this isn’t a realistic scenario in a PC, it doesn’t reflect well on the unit’s design.
Disassembly
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The ATX2000’s input filtering consists of one X capacitor, one common-mode choke and two Y capacitors (plus a space for a third after the rectifier). It is generally recommended to install an extra choke there, but there are enough capacitors. The other key components are a 6A bridge rectifier, 560µF H.Q branded primary capacitors and Jilin Sino Micro 3DD209L switching transistors rated at 12A each.
The 12V rectifier is MOSPEC F16C20C. This is a fast recovery rectifier which is rated at 16A. I got away with pulling more than the labelled 18A from it, but this is not recommended. It would also be better to use a Schottky rectifier, as opposed to a fast recovery rectifier, as they are more efficient and thus produce less heat. The other two rails use SBL3040PTs, which are Schottky rectifiers rated at 30A. At least these rails use adequately spec’d rectifiers. The secondary side Capacitors are all branded H.Q, like the primary capacitors. These are not well regarded parts.
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The fan is a sleeve bearing part branded Fujian. The bearing had plenty of oil in it, so the reliability shouldn’t be too much of a problem. It is wired directly to the 12V output, but it was fairly quiet. Due to the poor 12V voltage regulation, the fan actually ran slower as the load increased and the unit warmed up. The heat sinks aren’t too bad, but there is ample room there for larger ones. The OEM did actually put their name on the PCB. It appears that this power supply was made by Cemo Power – a company I’ve never heard of before.
Specifications and Conclusions
| Real Wattage | 200W |
| OEM | Cemo Power |
| PFC | None |
| Price | Unknown |
| ATX Connector type | 20+4 pin |
| Worst-case voltage regulation (12v, 5v, 3.3v) | 11.5%, 2%, 0.9% |
| Worst-case ripple (12v, 5v, 3.3v) | 55.2mV, 40.8mV, 28.4mV |
| Worst-case efficiency | 68.69% |
| Input filtering | Indequate |
| CPU Connector | ATX12V (4 pin) |
| PCIe Connectors | None |
| Molex (Peripheral) Connectors | 4 |
| FDD Power connectors | 2 |
| SATA Power connectors | 1 |
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Pros: None.
Cons: Absolutely appalling 12V voltage regulation (−3), Can’t deliver labelled rating (−2), Low quality capacitors (−2), Inefficient (−1), Inadequate input filtering (−0.5), Average ripple suppression (−0.5)
Score: 1/10
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