One or more USB devices may not work after you start your Windows XP-based computer
Symptoms of the problem
Note These USB devices may be attached directly to USB ports on the computer or to an external USB bus-powered USB hub.
- You have too many USB devices attached to the USB hub. This issue occurs because the combined sum of the power requirements of the USB devices is more than the available power that is provided by the hub.
- You have a high-power USB device attached to a USB hub or to a USB port on the computer. For example, you have a USB hard disk, and the USB device exceeds the power limit of the hub or port. This issue typically occurs if the USB device can run with or without an AC power adapter.
- Your computer uses an internal hub. For example, a portable computer may have a single USB bus and may use an internal USB hub to provide two or more available USB ports on the computer. Suppose that you use the device without the AC power adapter. In this scenario, the available power from a single port may be less than expected if other USB devices are connected to the other USB ports on the same internal USB hub.
Steps to resolve the problem
Method 1: Connect the AC power adapter to the USB deviceYou may have too many USB devices attached to the USB hub. The sum of the power requirements for the devices exceeds the power capacity of the hub. When you connect the AC power adapter to the USB device, the power requirement for the USB device from the USB port is greatly reduced.
Method 2: Connect the AC power adapter to the hubYou may have a high-power single USB device, such as a hard disk, that has the option of running with or without an AC power adapter. If you are not using the AC power adapter, the USB device may require more power than the power that is provided by the hub or by the port. When you connect the AC power adapter to the hub, more power is available.
Method 3: Replace a passive (unpowered) hub with an active (powered) hubIf you are using just one USB device, you might not need a power supply. However, if you are using several USB devices, the power requirements for the number of USB devices you are using may require a powered USB hub.
Method 4: Determine which USB device is not working or is causing the issue, and then connect the device directly to a USB port on the computerTo determine which device is causing the issue, follow these steps:
- Disconnect all the devices from the USB hub.
- Restart the computer.
- Connect the devices one at a time until you receive the following error message: USB Power Exceeded
- Try different combinations of connected devices to determine the most effective configuration.
ИД на статията: 885624 – Последен преглед: 01/30/2008 18:17:54 – Редакция: 4.3
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