Proliant DL380 G7 Won't Start Without Both Power Supplies

[jstevens7]

Hi,

I have an HP Proliant DL380 G7 that has dual 460 watt power supplies.  If I have both power supplies plugged in at the same time, then the server will boot and get through the POST just fine.  If only one of the power supplies is connected (doesn't matter which), the system starts and seems to be working, but when the POST reaches the "power and thermal calibration" stage, the server suddenly powers off without warning.  The power button turns amber and the system health light flashes read. The health indicator light for the connected power supply also turns on (the light for the disconnected power supply was always on).  No other lights are on (for example, the power cap light remains off).

I have updated the BIOS and reset everything to defaults, but this issue persists.  Does anybody have any ideas where to look? This system is out of warranty and I don't want to purchase a support contract since everything else is working just fine.  Thanks.

EDIT: It doesn't make a difference if I try it with one of the power supplies removed; the result is the same.

[Jimmy Vance]

Depending on the server configuration, both supplies might be required to provide the required power for all system components

[Rob_at_NSIT]

If you are exceeding the power limits of the power supply (input or output) it will cut off at high load.  This could occur in the OS in peak conditions (especially if power redundant mode is set to high efficacy), or when the BIOS purposely load tests the system in the power and thermal calibration phase at boot up.   

I've seen this issue from four places.

Most common, the server was ordered as value base with the 95W or 130W CPU and a second CPU is added.

Two, a ground strap (little piece of copper that looks like a inside out bow) is mangled shorting a trace on the system board or power board.  This is normally a factory or service defect as they shouldn’t be mangled.  I usually will remove it if it is mangled.  (Removal system board is required to diagnose.) This could cause random BSODs and / or no power on situation as well.

Too much memory or too many add-in cards installed resulting in the output being exceeded.

Bad power supplies; very rare in my experience, but in some cases the power supplies just can not handle the full 460W load.  


You should (it you watch the boot up) a notice that the system report that it is running in dual power non redundant mode if you are exceeding the power limits.   Sometimes the server cannot tell that it is overloaded if the overload is caused by the CPUs alone.

To test the CPU load got to the "BIOS" and set power mode to Minimum power usage or HP Static Low power mode.   Boot to the NIC or OS after saving power settings, and then try the single power supply.

Try each power supply by itself in bay one then bay two, if it is linked to a bay check for shorts (or you have a bad power board).

Also be aware the 94% power supplies need clean 120v power (APC output / Residential) at 108 (office building / cheap surge suppressor) they can only handle about 390W.  Using the wrong power cables can also cause the power supplies to get insufficient voltage at full load.  Both situations will cause the PS cut out before the servers full load expectation, making the server think the PS is bad.  Check the power cables and make sure they have HP P# and are about 3/8” if they are 1/4” they can be adequate at 3 feet or less. If they are smaller then 1/4” stop using monitor power cables on your server.


Add up power in use.  (The below are peak loads, nominal loads depend on actual usage.)
The system board (by itself) is about 75W (410i / ILO included).
HHDs are about 12w.  (7w for MDL or SSD)
Each memory DIMM will use between 5 – 25w nominal peak for LP/LR 4GB RDIMM is about 8W for normal 4GB RDIMMS about 12W.
Each add in card will use 10 -& 75 W.
    Over simplified rule of thumb, if there is no heat sink consider the card 15W, if it has a heat sink consider it 35W and if it is a Video card with no power cables consider 75W, if it is a video card with one cable 150W and 2 cables 225W.  
CPUS available for the G7:
Intel® Xeon® X5690 130W,
Intel® Xeon® X5680 130W
Intel® Xeon® X5675 95W
Intel® Xeon® X5670 95W
Intel® Xeon® X5660 95W
Intel® Xeon® X5650 95W
Intel® Xeon® E5649 80W
Intel® Xeon® E5645 80W
Intel® Xeon® L5640 60W
Intel® Xeon® X5687 130W
Intel® Xeon® X5677 130W
Intel® Xeon® X5672 95W
Intel® Xeon® E5640 80W
Intel® Xeon® E5630 80W
Intel® Xeon® E5620 80W
Intel® Xeon® E5606 80W
Intel® Xeon® E5603 80W
Intel® Xeon® L5630 40W
Intel® Xeon® E5506 80W
Intel® Xeon® E5503 80W



For example a DL380G7 with two X5650 12 4GB RDIMMs and a pair or 146GB 15ks would boot up with two 94% power supplies (217W each) and the server would think every thing is fine as your only using 433W (no non redundant error message) but with low AC power a single 94% power supply would cut out because your exceeding the ~4.5A input.

Note about input power. I've only ever seen two servers that checks it, the IBM 3850/3950 X5 and the first (not the later generations) HP DL585.