xw8400 USB Ports -- +5VDC Current Specifications (Device Charging Application)

[DBrunnenmeyer]

How does one determine the acceptable maximum load current for charging external devices using a typical USB 2.o or USB 3.0 port on HP workstations?  My HP EliteBook 8570W has a USB port designated as a charging port, but I cannot find any information on acceptable load currents for such ports on our family desktop workstations. In this instance, I am interested in the limitations of the front and rear panel USB 2.0 ports on the xw8400, xw8600xxx and xw9400 line of workstations.

To be more specific, an engineer decided to continuously recharge a hand-held UV wand using the front panel USB 2.0 ports on an xw8400. This UV device was used to periodically "disinfect" the working surface of an audio mixing console. I have no idea what the current demand was, but apparently the front panel ports are no longer reliable or perhaps even functional at all.

To avoid issues like this in the future, it would be prudent to provide information on the upper limit of USB port charging capabilities. In the meantime, what is/was the charging current specifications for xw8400 USB ports. I don't expect exact answers, but guidance would be appreciated.

[DGroves]

In general, the specifications for a USB 1.0 and 2.0 standard downstream port, delivers up to 500 mA or 0.5A. Also, with  USB 3.0, it can provide up to 900mA or 0.9A, which translates into 4.5 watts. These power output specifications are a rating based on the 5 volts from each standard output

or simply READ the USB 2.0/3.0 power specifications, it lists the max allowed currents for usb 2 and 3

https://www.usb.org/documents

note usb 3.0/3.1/3.2 is a bit harder, as it has various current levels available that a vender may or may not enable

you have to also understand that a max usb charging current is not the same as the general max output the laptop determines the correct current levels from the usb cable using wiring and pullup resistors and also from the device itself for usb 3.1

you can find all of this information in the usb org's online documentation and also various articles' that have been written by many many online reviewers over the years on this subject

[DBrunnenmeyer]

I'm now told that there's no +5VDC on the non-working USB ports, both front and at the rear, but otherwise the xw8400 seems fully functional*. An unknown-to-me USB 3.0 card installed by the station's engineer in the back apparently provides the only working USB interface. I could not find any information regarding a separate fuse for the USB 2.0 port power nor a fuse of any king on the motherboard to protect the supplied power to those ports.

The power supply connector has several +5VDC pins but their individual functionality is not identified. Is it possible that one of those outputs is intended for the USB ports and maybe other functions, and that a fuse INSIDE the power supply is blown?

*Because of COVID-19 restrictions, I cannot go into the studios (in fact, the whole building), to troubleshoot this issue myself., at least not yet. I'm trying to help from my home office and studio.

[DGroves]

i'm EX "IT" and i worked on and also owned a xw8400, so i'm quite familiar with them

before we go any further, the xw8400 while a great system in it's day is now way obsolete, i would not spend any money on repairs even it's successor the xw8600 is no longer worth repairing

you will be much better served with a  z800/z600 or better yet a z820z/z620 system in my opinion

as to your current 8400 usb issue, the motherboard is defective, the chip that contains the usb functions has failed and as i stated a replacement board is not worth the cost

the motherboard usb +5 comes directly from the motherboard/chipset there are no external +5 inputs from the power supply

i believe i covered this with you previously in a prior post

all you can do is add a pci usb 2.0 card to the xw8400, and if you do,...... source one that has a power jack on the card if you will be connecting high current draw usb devices note that simply finding a PCI usb card will be difficult, much less one with a aux power jack as most usb cards nowadays are PCI-E not PCI

[DBrunnenmeyer]

We have several of these workstations in service, and their performance requirements are very modest—simply playing audio files and browsing the web for current new bits and pieces. They have fully-functional USB 3.0 cards on the back side.

Oh, and I should mention that there are a number of special configurations, drivers and so on, specific to the studio and the Axia broadcast consoles. Migrating to new on-air PCs is not quite as simple as it might sound, but then that's somewhat true for office setups, too.

This is a community-supported FM radio station application that needs to be as frugal as possible but also reliable. A small family of z820 workstations will be our next upgrade, but that's not likely to be affordable until all of the pandemic dust settles and we're all back in the station and free to interact with each other again. Thanks for your advice.

D2B ...