2 problems about LimeSDR

I ordered dozens of LimeSDRs. I have now find problems of 2 boards.

1.One of my board’s LED is not lighten at all when I plug into my computer.
LimeUtil --find / SoapySDRUtil --find shows nothing.
Sometimes my computers says this USB device draws too much current. But the same computer supports other LimeSDR.

2.Another problem is, when I am transmitting a constant signal. The amplitude shown in oscilloscope is always changing, this causes error codes, when transmitting digital data. We have B210 in comparison, the amplitude doesn’t vary that much. I think this might not be a single board problem, since the other LimeSDR shows similar results. If there is some way we need to configure, please advise.

I am told that I am not allowed to upload videos, so I uploaded 2 screen shots which also shows the amplitude is changing

This is when LimeSDR is transmitting, you can see the amplitude is not stable.

This is when B210 is transmitting, its amplitude doesn’t vary much.

Upload video to youtube and paste the short link

Please take a look, thank you.

You are transmitting a Continuous wave at 500 MHz, I’m curious what sample rate were you using for TX ?

The carrier frequency is around 240MHz, I used it to transmit a constant wave. The transmitting sample rate is 10MHz.