LimeSDR USB IC 25 bad Need orientation to R&R

Well, I was having issues recently. Hanging up, shutting down & all sorts of weird things. I put in the FX RAM several times.
I spent 2 days trying to figure it out.
This morning, when I plugged it in, I saw the lights go out on the external USB3 harddrive (Both lime & harddrive on same PCIe USB3.0 card.
At work this morning, I had an idea. I plugged it into a powered hub. Plugged in the power supply & tested pin 2 (Board side) of the USB plug. There was 7.85 volts going into the 5V+ line. The IC 25, which directs whether the USB power, or the External power goes to the regulator is shot.

I can pull it & flow another on, but with no printing on it, I do not know the PCB “Pin 1 orientation”.
If I could get some direction, I can get back to using it.

Also, another tech tip, if you have to keep fixing the FX3, check the voltage on pin 2 (PCB side) to see if you have external power supply voltage.

Thank you,

Should I just throw a couple diodes in there?


Anything at all? There is no nomenclature on the chip, as I see. Should I just pull the chip & hope that I can figure it out with an ohmmeter? I really do not want to fry this.


@Zack, perhaps you could advise?

Hi @AA7QQ,

Let me check I will come back to you next week, sorry for delay.

THank you.