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I am having unexpected opportunities with a USB Device failing to properly initialize on startup after a shutdown, which seems to be caused by residual power remaining on my USB Ports (after shutdown).

Model: HP Compaq Pro 4300 SFF

Product ID: QZ219AV

  • Windows 7 Pro (32-Bit)
  • 4 GB Memory

USB Ports DC Voltage prior to shutdown is 5.15 VDC

USB Ports DC Voltage after shutdown is 1.7 to 1.9 VDC

I have had the same or very similar issue with about a dozen HP Laptops:

Model: HP Pavilion g4-1318dx Notebook

Product ID: A6Y11UA#ABA

  • Windows 7 Pro (32-Bit)
  • 4 GB Memory

Note that I have many other HP Computers which do not have this problem.

Model: HP Compaq 4000 Pro SFF

Product IDs: A7L22UT#ABA, A7H78UT#ABA, and LA072UT#ABA

  • Windows 7 Pro (32-Bit)
  • 4 GB Memory

USB Ports DC Voltage prior to shutdown is 5.08 VDC

USB Ports DC Voltage after shutdown is 0 VDC (actually it 0 mVDC)

Any suggestions on how to resolve this issue on the HP 4300? Switching to another vendor/manufacturer/device is not possible at this time.



share|improve this question
Have you spoken to HP support? – Dave M Dec 7 '12 at 0:20
Yes, unfortunately they have been less than helpful – Ron Dec 7 '12 at 20:29
PROBLEM SOLVED: It's a feature in BIOS. I found a setting called "S5 Maximum Power Savings". When this is set to DISABLE (which is the default value), the system will maintain about 2VDC to the USB Ports (as will as keeping other components alive). When it is set to ENABLE, the system will kill power to all components as well as the USB Ports. – Ron Dec 19 '12 at 15:59

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