EVGA 750N1 750W Power Supply

EVGA 750N1 – Overshoot Transient Tests
VSB On	VSB to Full, 12V	Off to Full, 12V

We’ll start this page with a look at the power on transient tests. And unfortunately, it looks like this unit’s missing the boat all the way along. The standby rail has a clear spike at the top of the waveform, almost at spec but not quite, and the 12V rail also has some weirdness going on. There goes the S&C point later.

Now, the fun part… hot tests. Let’s fire up the hot box and see where it shuts down.

EVGA 750N1 – Hot Load Tests
Test #	+3.3V	+5V	+12V	DC Watts/ AC Watts	AC Input	Eff.	P.F.	Intake/ Exhaust
Progressive Load Tests
1	1A	1A	5.5A	76.5W/ 95.1W	115.3V	80.5%	0.974	27°C/ 30°C
	3.366V	5.04V	12.15V
2	2A	2A	11A	152.4W/ 180.5W	116.9V	84.4%	0.984	30°C/ 36°C
	3.350V	5.02V	12.10V
3	5A	5A	27.5A	378.7W/ 446.0W	117.1V	84.9%	0.990	34°C/ 45°C
	3.301V	4.98V	11.99V
4	7.5A	7.5A	41A	559.0W/ 677.2W	116.2V	82.6%	0.994	38°C/ 51°C
	3.258V	4.95V	11.89V
5	10A	10A	55A	742.3W/ 943.8W	113.6V	78.6%	0.996	41°C/ 63°C
	3.207V	4.92V	11.75V
Crossload Load Tests
CL1	18A	18A	0A	139.0W/ 189.6W	116.6V	73.3%	0.982	29°C/ 40°C
	3.281V	4.37V	12.70V
CL2	0A	0A	59A	676.6W/ 845.0W	114.6V	80.1%	0.995	39°C/ 57°C
	3.274V	5.29V	11.45V

And… it didn’t shut down. Forty-one degrees, and it went the whole ten minutes of that test.

But it did not do so comfortably, and we need to talk about that. Look at the efficiency numbers… the unit now fails 80 Plus White. And that’s not all… right up to the ten minute mark, power draw was increasing every thirty seconds or so. Every time the ambient temperature went up a degree, I would see a corresponding major increase on the power meter. By the end, power draw was going up though the temperature was stable. I’ve seen units do this before right when they’re getting ready to fail, and there is no doubt in my mind whatsoever that another five minutes probably would have made this balloon go pop.

So, now we know two very important things. One, the unit can’t handle forty degree temps over the long haul no matter how badly it wants to think it can. Two, the overtemp protection is either not there at all or not functioning. This will be scored on.

Over on the voltage regulation side of things, no new surprises. I now see 4.82% on the 3.3V rail, 18.40% on the 5V rail, and 10.42% on the 12V rail. This leads us to an 11.2% number for scoring that will see all possible scoring points on regulation disappear.

Let’s find out what the scope saw.

EVGA 750N1 – Oscilloscope
Test #	+3.3V	+5V	+12V
1
2
3
4
5
CL1
CL2

I’m seeing 20mV on the 3.3V rail, 45mV on the 5V rail, and 50mV on the 12V rail. Not bad at all, actually, though only one of the three rails clears excellence. The other two will get point deductions, but just minor ones, later.

Let’s take it apart and see what the guts look like.