siren sound at sleep start

[johnffds]

PC makes loud siren tone when sleep mode starts. 

siren stops when mouse/keyboard restarts windows.  Very repeatable issue.  Only started in recent days.  Few weeks ago a wifi/bluetooth card was installed but can't see that this is relevant.  The fan is working ok.  Processor core temperature around 35C.

I can't see anything obvious in the event viewer, but advice on what to look for will be helpful.

[erico]

Take a look in the BIOS Advanced tab.  The alarm after power loss might be enabled.

Here is a BIOS simulator for your PC

http://h10032.www1.hp.com/ctg/Manual/c06527332.pdf

Yours is the first I have heard of  in a long time that still has a piezoelectric buzzer. You should be able to disable it. 

[johnffds]

I seem to have 'fixed' the siren, as no longer occuring - fyi, it was from the speaker not a piezo, as I pulled the speaker connector to check.

I now realise that the deskpro does not enter 'sleep' mode on the power timeout, only if I select Sleep from the power off menu option.

I'm having a look at the event viewer and all that is happening at the power timeout is:

event ID 7040 The start type of the Touch Keyboard and Handwriting Panel Service service was changed from auto start to demand start. (earliest)

event ID 263  A pointer device has no information about the monitor it is attached to.

event ID 267 Touch/Touchpad Hardware Quality Assurance verification succeeded. (last)

So I guess there is something preventing the timeout sleep from happening?  The monitors are being switched off correctly.

I had a look at the bios before the original post and didnt' consider there was a solution there.