OCZ ZT Series 650W (Page 3 of 4) | Reports

Page 3 - Physical Look - Inside

As with all power supplies that we open up, the warranty must be voided to take a look inside, and the OCZ ZT Series 650W power supply is no exception. Just remember that doing this will void your 5-year warranty once the seal over one of the screws is broken. Here at APH Networks, we void the warranty to take a look inside, so you don't have to worry about yours. The OCZ ZT Series 650W is made by Chinese manufacturer Great Wall. As you can see from our photo above, it shows an overhead view of the PSU itself. The components are decently spaced out with some extra room to spare on the left side for the best possible cooling with the least amount of heat congestion. Unlike most PCBs, the one inside the ZT Series is nicely colored black. There are only two black painted finned anodized aluminum heatsinks under the hood. This simple heatsink arrangement along with such a configuration of interior components allows for lower airflow impedance benefit.

First taking a look at the transient filter stage we can see that the OCZ ZT Series 650W has two ferrite coils, two Y-capacitors and one X-capacitor, which is more than the minimum required. However, the downside is that it is missing a metal-oxide varistor, which is used to stabilize spikes from the AC line. It would have been nice to have one included, but since this is a mid-ranged PSU, this is sufficient enough to get the job done. Every component is nicely soldered on quite neatly in my opinion.

On the primary side, we can see a Taiwanese made Teapo capacitor. Japanese brand capacitors are usually the best choice in terms of build quality, but for such power supplies, Taiwanese capacitors are fairly popular and reputable in this regard in doing the job. Our Teapo capacitor is rated at 560μF x 420V @ 105c. It is definitely nice to see a 105c capacitor here, since manufacturers typically cheap out and install 85c units instead.

The active PFC circuit uses two SiPower T10KB60 rectifying bridges; each supports up to 10A of current at 100c, and are attached to the heatsink. These are controlled by the Champion CM6800 PFC/PWM controller. At 115V, the maximum rectified forward current capacity is 10A. From doing the math, you can theoretically pull up to 2300W from the bridge rectifier at 100% efficiency, but of course, nothing is ever perfectly efficient. On top of that, not every component in the power supply can keep up the workload. Two Fairchild Semiconductor FDA24N50 power MOFSET transistors are used on the active PFC circuit, each can deliver up to 14A at 100c or 24A at 25c in continuous mode, or 96A at 25c in pulse mode. These transistors have a maximum resistance of 0.19 ohm when turned on, according to the manufacturer's data sheet. This feature is characterized as Static Drain-Source On-Resistance, or commonly abbreviated as RDS(on). The lower the value, the more efficient the component is, as it wastes less power with less resistance.

On the secondary side, there is a handful of Rubycon and Nippon Chemi-Con 105c capacitors. I would have expected OCZ to resort to Taiwanese Teapo capacitors for such a PSU based on what we have seen on the primary side -- but hey, I don't have anything to complain about high quality Japanese brand capacitors. I find this configuration rather funny, as this is definitely not the traditional way of doing things. OCZ said they did this because secondary capacitors are more prone to failure. The +12V output uses two QM6020AP MOSFETs located on the small solid black heatsink for the rectification process. These are rated at 125A at 100c, or 198A at 25c in continuous mode, and 350A at 25c in pulse mode. The RDS(on) value is only 0.0038 ohm. There are also two PFC Device Corp PFR60L60CT rectifiers here, each rated at 30A at 100c. The +5V output uses PFR30L45CT Schottky rectifiers, each rated at 15A at 100c. Last but not least, the +3.3V output uses PFR20L45CT rectifiers, each rated at 10A at 120c. Chemi-Con electrolytic capacitors rated at 105c are used to filter the outputs. A ST9S424 monitoring integrated circuit is used, but unfortunately, the datasheet was not available from the manufacturer's at the time, so we can't specifically comment on the protections provided.

Taking a look at the back, we have a daughterboard covering the rear panel for the modular connectors on the other side with its connections soldered onto the mainboard cleanly. Overall, the internal build quality of OCZ's ZT Series 650W power supply is pretty good. Components are arranged in a very organized fashion, and the rest of the soldering job is done very well overall. In my opinion, the overall build quality of the OCZ ZT Series 650W is decent for its price and the internal components used.

Lastly, we see a large 140mm fan that provides cooling to the OCZ ZT Series 650W's internal components connected to the mainboard via a 2-pin connector. A large fan such as this one in most cases would provide more airflow at lower speeds in comparison to small fans, which in turn will provide quieter operation. The fan OEM is Yate Loon, and is known for making sound optimized products among enthusiasts. The model number "D14BH-12" is printed in the center. Additional research shows that this is a ball bearing fan specified at 0.7A for a maximum of speed of 2800 RPM, 140.0 CFM airflow, and 48.5 dB of noise.

Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion