On 07/01/2020 02:03 PM, Nate Young wrote:
Thank you for the suggestion, unfortunately, the stock image (from
/usr/local/share/uhd/images/usrp_b205mini_fpga.bin) had the same error
message.
I also ran uhd_images_downloader to make sure the images were up to
date, as well as verified the udev rules were correct.
I started probing the board, and found that the output of the U9 clock
buffer chip is not correct. It is 40MHz, but has a slower speed
(~1MHz) on/off modulation to it.
It turns out the capacitor C90 is no longer on my board ! This
capacitor provides stability to the LDO in the CDC3RL02 clock buffer
chip, and according to TI, will cause modulation on the output waveform.
So this is likely the cause. It looks to be an 0402 or 0201 part, so
I have ordered some of those in 2.2uF and will see if I am able to
replace it.
One of the issues with teensy SMD parts is that they can be "brushed"
off a board relatively easily with a mechanical impact that would be
no problem at all for lower-density through-hole parts. This is one
of the reasons I don't like to run these modern boards outside an
enclosure in a "busy" lab space.
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