Contents
Thermal Master TM-420-PSAR-I3
Thermal Master power supplies are low end Cooler Masters, and often come bundled with Cooler Master cases. The last Thermal Master I’ve seen was made by Sun Pro, and exploded when under full load. This one, however is made by Solytech, formerly known as Deer.
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Like the Shaw, the label incorrectly claims that this power supply has two 12V rails. It really only has one 12V rail. The label also contains Cooler Master’s usual Engrish – “As sealed stick was removed, lost or damaged, it shall be out of warranty validity”.
Load Testing
Test 1 (118.53W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 4.9A | 12.24V | 14.6mV |
| 5V | 5.06A | 5.06V | 13.2mV |
| 3.3V | 10.0A | 3.30V | 13.2mV |
| −12V | 0A | −12.17V | 9.4mV |
| 5Vsb | 0A | 5.04V | 6.0mV |
| AC Power | 149.35W | ||
| Efficiency | 79.36% | ||
| Power Factor | 0.65 | ||
Test 2 (203.24W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 9.82A | 12.28V | 17.8mV |
| 5V | 10.0A | 5.00V | 13.2mV |
| 3.3V | 9.94A | 3.28V | 14.2mV |
| −12V | 0.1A | −12.4V | 13.8mV |
| 5Vsb | 1.0A | 5.00V | 9.2mV |
| AC Power | 260.59W | ||
| Efficiency | 77.99% | ||
| Power Factor | 0.67 | ||
Test 3 (262.49W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 14.68A | 12.23V | 20.8mV |
| 5V | 10.04A | 5.02V | 13.6mV |
| 3.3V | 9.94A | 3.28V | 15.2mV |
| −12V | 0.11A | −12.72V | 15.4mV |
| 5Vsb | 1.0A | 5.00V | 8.8mV |
| AC Power | 337.84W | ||
| Efficiency | 77.70% | ||
| Power Factor | 0.68 | ||
Test 4 (319.79W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 19.46A | 12.16V | 23.2mV |
| 5V | 10.06A | 5.03V | 14.8mV |
| 3.3V | 9.94A | 3.28V | 15.6mV |
| −12V | 0.11A | −13.08V | 19.8mV |
| 5Vsb | 1.0A | 5.0V | 10.4mV |
| AC Power | 421.27W | ||
| Efficiency | 75.91% | ||
| Power Factor | 0.66 | ||
Test 5 (347.3W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 19.6A | 12.25V | 28.2mV |
| 5V | 14.94A | 4.98V | 16.2mV |
| 3.3V | 9.97A | 3.29V | 15.8mV |
| −12V | 0.11A | −13.28V | 26.8mV |
| 5Vsb | 1.0A | 5.00V | 11.0mV |
| AC Power | 458.35W | ||
| Efficiency | 75.77% | ||
| Power Factor | 0.65 | ||
Test 6 (404.31W Load – Cold)
| Rail | Load | Voltage | Ripple |
| 12V | 24.36A | 12.18V | 35.0mV |
| 5V | 15.0A | 5.0V | 19.2mV |
| 3.3V | 9.94A | 3.28V | 16.4mV |
| −12V | 0.11A | −13.53V | 40.6mV |
| 5Vsb | 1.0A | 5.0V | 12.2mV |
| AC Power | 546.93W | ||
| Efficiency | 73.92% | ||
| Power Factor | 0.66 | ||
Oh Deer (pun intended), it came so close to the finish line. This power supply made it all the way up to 400W, but exploded when loaded to its labelled rating. Prior to the fireworks, though, it was actually doing OK in terms of voltage regulation and ripple suppression, with the exception of the −12V rail. It managed 2.3% regulation on the 12V rail and less than 2% on the other rails. The −12V rail was out of spec in the last two tests, but to be fair, it’s seldom used these days, so I doubt it would be too much of a problem on most modern PCs. It managed just 35mV of ripple on the 12V rail and less than 20mV on the others, which is the best so far in this roundup. The efficiency, though, wasn’t so great, peaking at only 79.36%.
| Rail | Test 5 (347.3W) | Test 6 (404.31W) |
| 12V |  |
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| 5V |  |
 |
| 3.3V |  |
 |
| −12V |  |
 |
| 5Vsb |  |
 |
A look inside
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The input filtering starts at the AC inlet. The PCB there contains an X capacitor, a common-mode choke and two Y capacitors. The main PCB contains another two X capacitors, a common-mode choke, three Y capacitors (including the one after the rectifier) and two MOVs, so the total number of components is three X caps, two common-mode chokes, two Y caps and two MOVs, which is more than enough components. In the switching section, there are two Jilin Sino Microelectronics D209L transistors, rated at 12A. The primary capacitors are 680µF parts from Anodia.
Moving on the the secondary side, the 12V rectifier is an SB3060PT. I couldn’t positively identify the manufacturer, but the part number implies that it is rated at 30A. The 5V and 3.3V rails both use an STPS3045CW Schottky (also rated at 30A), so all rails are capable of up to 30A in theory. The capacitors are all from Yang Chun, a brand which I’ve had mixed experiences with. I’ve known them to last years on some PSUs, while on others they didn’t hold up so well, so it’s anyone’s guess how they will hold up in these power supplies.
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The fan is a sleeve bearing part made by Globe Fan, rated for 2000RPM, with noise and airflow ratings of 34dB and 67.28FCM respectively. It was barely audible throughout the testing.
Specifications and Conclusions
| Real Wattage | 400W |
| OEM | Solytech |
| PFC | None |
| Price | $35 |
| ATX Connector type | 20+4 pin |
| Worst-case voltage regulation (12v, 5v, 3.3v) | 2.3%, 1.2%, 1.8% |
| Worst-case ripple (12v, 5v, 3.3v) | 35.0mV, 19.2mV, 16.4mV |
| Worst-case efficiency | 73.92% |
| Input filtering | Adequate |
| CPU Connector | ATX/EPS12v (4+4 pin) |
| PCIe Connectors | None |
| Molex (Peripheral) Connectors | 3 |
| FDD Power connectors | 1 |
| SATA Power connectors | 3 |
Pros: Reasonable voltage regulation, Quiet, Good ripple suppression, Good input filtering
Cons: Can’t quite deliver its labelled rating, Questionable quality capacitors, Inefficient, Could use more connectors
Score: 5/10
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