Troubleshooting | General/ Logic Board Troubleshooting - 18 |
|
|
DS4 and DS5 = USB power for downstream devices
DS5 = USB port 1- lower
DS4 = USB port 2- upper
(There is no DS2 or DS3 on the board.)
When illuminated, these LEDs indicate that the computer is providing power (+5 V) to downstream USB ports. USB devices do not need to be connected in order for these LEDs to illuminate. However, if one or both of the LEDs is not illuminated and a USB device is/was attached (and the system has completed its boot process), then the logic board has removed downstream power because of a trouble condition.
Since the downstream power is controlled individually for each port, it is possible to have these LEDs in a different state: one off and one on. This way if one port has troubled USB devices, the
