mohammad462 wrote: ↑
Sun May 20, 2018 9:39 am
The mark is not important. The main thing is that the usb does not work
, if the lightening symbol burns, your PI, and thus also your USB devices do NOT receive the at least 4.75V they need to operate
, as the lightening symbol tells you that the 5V, at least temporarily, dips below 4.65V.
You say you measured 5.2V, WHERE did you measure that, and under which conditions? And did you measure with an oscilloscope on the 5V signals on the PI to see if the 5V was steady, without dips in it below 4.75V?
That said, if both the USB, and the ethernet are not functioning, I would assume the LAN9515 is not working either, (as that chip is responsible for both USB and Ethernet) especially if you enter a live (that is a cable connected to an ethernet device) cable into the ethernet port, the ethernet activity LED's on that port should light up, if they don't I would suspect a dead LAN9515 chip.
That chip runs on 3V3, so its worth checking if your PI produces 3V3.
I tend to go with the idea you have either a broken LAN9515 CHIP, or 3V3 power supply. maybe an overload (short) in the 3V3 supply that draws the 5V line low, or a (halfway) burned out polyfuse.
p.s. I have never understood what you meant by:
but the blue dot is blue.
care to explain?