Flickering Datalink LED (Used to work perfectly fine before)

[kyrollosyanny]

Hi All,

My name is Kyrollos. I am a grad student at UCB. I assembled a miniscope about 2 months ago. It was working perfectly fine. However a couple of days ago, the datalink LED started to flicker and now everytime I connect, I get the red screen of doom right away. I can still change the brightness of the LED though. Do you have any suggestions on how to fix this?
There also seem to be no short in coaxial cable (the pads for it are UV glues and I tested with a voltmeter and there is no short).

Thank you so much

[kyrollosyanny]

It seems like there is a hole in our L13 inductor. It seems it was burnt due to some type of wrong connection. Can you suggest what could have caused that? (ie if I replace the inductor, is it safe to connect the coaxial cable again)?
Also, when testing for shorts in the coaxial cable, the outer and inner conductors are not shorted, however, I ground and the two half circle on the back of the CMOS pcb are connected, is that normal? Thank you so much

[Daniel Aharoni]

Hi Kyrollos,
The L13 inductor can get damaged if too much current is pulled through it. This almost exclusively happens when there is a short across the coax cable close to where the cable connects to the DAQ PCB. You may accidentally and temporarily shorted these signal and ground lines within the coax cable, in the SMA connector, or on the DAQ PCB.

I suggest looking up the part number of L13 in the Bill of Materials (BOM) file on GitHub and replacing it. There is a chance something else was also damaged but likely not.

The L13 inductor being fried shouldn't damage any other equipment connected to the DAQ PCB.

[Stephanie Staszko]

Hi Kyrollos and Daniel,

It appears I have also damaged the L13 inductor of my DAQ with a shorted coax cable. We have the DAQ V3_2. Is it possible to replace the inductor ourselves? I tried looking for the part in the BOM but was unable to find it. Thank you for your help!!

[Daniel Aharoni]

Hi Stephanie,
We have had some success with just replacing the L13 inductor in these cases. Here is a link to the part on digikey: https://www.digikey.com/product-detail/en/CBC3225T101MR/587-1628-1-ND/1008243

[Stephanie Staszko]

Yay! Thank you so much 

[Stephanie Staszko]

Just giving an update - I replaced the L13 inductor and our DAQ board is up and running! I am definitely going to be much more careful about checking the coax cables for shorts from here on out. Thanks again for all of your help