Contents
- 1Introducing the Zalman ZM750-EBT
- 1.1Packaging and accessories
- 2Connectors & cabling
- 2.1Casing & cooling
- 3Input filtering
- 4Primary side
- 4.1+5 V stand-by rail
- 5Secondary side
- 5.1Build quality
- 6Load testing
- 6.1Loading +5 V SB
- 6.2Voltage hold-up time
- 6.3Combined loading
- 6.4Combined loading ripple
- 6.5Crossloading, overloading
- 6.6Crossloading, overloading ripple
- 6.7Fan speed, temperatures and noise
- 7Conclusion and evaluation
- 7.1Thanks
- 7.2Discussion
- 8Important addendum
Conclusion and evaluation
The Zalman ZM750-EBT did not pass the combined and crossload testing in accordance with the ATX specification, so according to my evaluation methodology, it is not deserving of an evaluation. What I like about this unit is the reasonable ripple suppression, which is on par with other units of this same platform from Sirtec, and while it does sometimes cross into mainstream values, it is still rather an acceptable result. In most of the other areas however it is worse.
The efficiency is slightly lower than what you would expect, which has now been confirmed by two other sources. The same goes for voltage hold-up time, which is incredibly low at just 10 ms, but to actually stay within spec because of voltage spikes, the real in-spec hold up time is just under 7 ms. This is by far the worst result we have seen yet. Another serious problem is that this unit’s over power protection seems to be non-functional. As a result, we were able to drop the 12V to just slightly above 10 V without it kicking in, which once again is totally unacceptable. And lower than that, the unit did finally shut down, but not because of UVP, but rather from the overheating protection.
Heat is another serious problem as with overloading, and some parts of the unit overheated so much as to cause a very bad smell. The area that overheated is too far away from the temperature sensor because otherwise the unit’s fan would have immediately kicked in to high gear. To compound all these problems, Zalman elected to use low-quality Teapo SC capacitors. I should point out however that they do offer a generous warranty period of 7 years. So even though low-quality capacitors in a high-end is not something I’m keen on, with its reasonable price and long warranty, this unit would have been worth considering – if it was not for all the other problems.
 Pros |
+ modular cabling + acceptable ripple suppression + long warranty + OK efficiency + OK build quality |
 Cons |
− mediocre voltage regulation − over power protection not working − under voltage protection not working − local overheating in overload scenario − incredibly short voltage hold-up time to stay in spec − Power Good hold-up time not in compliance with ATX − bad capacitors |
 Be aware of… |
/?\ supposed multiple revisions |
Thanks
I thank the Zalman company for providing the Zalman ZM750-EBT unit.
Loading ...