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ML330 G6 Redundant Power Supply does not support Hot Swap

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Occasional Advisor

ML330 G6 Redundant Power Supply does not support Hot Swap

I've got three ML330 G6 servers. I installed the enablement kit for power redundancy, that is I removed single original power supply, installed the new enablement kit and two specific new power supplies. Please assume there are one *upper* power supply and one *lower* one (that is, upper and lower as refererred to physical position only).


Here is the problem:

1. Server is on, Windows Server 2003 up (or, if you prefer,  live cd "Hp SmartStart" is booted, it's the same)

2. I unplug upper power supply from mains (or from an UPS, no matter): server goes on, no problem, right behaviour; the server is powered by the lower power supply and this is right!

3. Now I EXTRACT (that is pull out) the unplugged upper power supply from the server. The server switchs off immediately, without os shutdown.This is no good.


This wrong behaviour does not occur if you repeat the steps above involving lower power supply instead of upper. This is stupid!

The wrong behaviour does not occur if you boot, enter the bios setup without booting your os, and repeat above steps.

You can watch a very short video here (sorry for site advertising):



I am on a support case with HP opened on July, 29 2011.

HP changed, more then once:

- power supplies

- enablement kit for redundancy

- main board

- ram

and they updated all the existing firmware.

No result, the problem is here.


With a problem like this, if upper power supply fails, you must shut down your system before swapping it with a new one. This is not "hot plug" or "hot swap" at all.


Any ideas?



Massimo Magagna


Abhishek Bangalore
Frequent Advisor

Re: ML330 G6 Redundant Power Supply does not support Hot Swap



Thank you for providing the detailed information about the issue. 


As per the description I am sure that the issue is with the power suply back plane.


Once the power supply back plane is replaced the issue will get resolved.




Help other's for Better Tomorrow

I am an HP Employee
Occasional Advisor

Re: ML330 G6 Redundant Power Supply does not support Hot Swap

Thanks Abhishek,

I'm glad you are *sure* about the enablement kit.

An HP service technician replaced the kit a couple of weeks ago, with no success.

But I suppose there is a problem in enablement kit, too, as you think.

I'd like to know if this enablement kit is a only hardware solution or if there is some firmware inside.

Seems to be a hardware revision problem.

Best regards.



Occasional Advisor

Re: ML330 G6 Redundant Power Supply does not support Hot Swap

Two weeks ago HP Support asked me to send one of the *five* servers of mine that have this problem.
They now admit that a problem exists (wow!).

They are saying my problem is at second level support, sometimes they say third level.


One of italian technician was curious about this problem and asked me to try and disconnect a segment of the internal control cable that comes from the enablement kit and goes to the motherboard. In this segment there is a *famous* derivative GREEN single cable that interface with power cables (if someone is interested in details, please ask me for the pictures).
Removing this segment gives an immediate result: the swap problem on upper power supply disappear! But we do not know about other side effects, so we cannot say this is the solution.

Keep in mind that support tech documentation explains in details how to connect this "segment with green cable" and that four technicians checked for the correct actual cabling.


It is amazing.

Greetings from Italy!

Frequent Advisor

Re: ML330 G6 Redundant Power Supply does not support Hot Swap

Interesting solution. Can you please post the pictures and if possible a video..:|

I also consider its apower backplane problem.


SF Hussain

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Occasional Advisor

Re: ML330 G6 Redundant Power Supply does not support Hot Swap

Solution occurred!

Hp Support certified that the "famous" extension cable must be removed on ML330 G6.

I verified that in recent shipping kits HP puts in a printed document that better explains: the extension cable must be used only with ML150 G6 server, and a yellow sticker on the extension cable repeats this warning.


Hp assured me that a document will be placed in the online documentation about ML330G6.


If you give a look at my photos (see link below), you will see:

- the WRONG configuration for ML330G6, *WITH* the famous "extension" cable with a yellow sticker

- the RIGHT configuration for ML330G6, *WITHOUT* the famous "extension" cable.



This was not a technical issue, it was *only* a problem in assembling instructions.


Thanks to HP support.


link for pictures: