Yun Broken? Current limiter gets very hot

Hi Community,

I think I might have broken my Yun :-(

The WIFI LED does not flash any more, and I get no feedback whatsoever from the YunSerialTerminal sketch.

I also noticed some parts near the USB host interface beeing very hot (I literally burned my fingertip). If I traced it correctly it should be the current limiter or the mosfet near it. That would be: - U15 Current limiter MIC2005A-2 (marking FA51) or - Q5 Mosfet AP2301GN (marking N1J6)

If connected to computer USB, the arduino part still seems to be working (blink example works), But I get no feedback from the linux part.

If I measure Vin or +5V I only get 4.07V, the 3.3V is merly 10 millivolts

Any chances I can repair that or should I consider it gone?

Thanks for any feedback, Tobi

P.S. Forgot to mention - this is a first generation Yun, bought in 2014 or 2013 IIRC.

If you have the skills and tools to replace those parts and its not anything else then it is certainly worth doing so.

You neglected to mention how it could have happened as that could also be useful information.

Otherwise 10 mV on a 3.3 supply means its is a dead board. AFAIR the Linux side operates off 3.3 volts. That may explain why only part of the board is still working.

How this happened is kind of a mystery to me.
I did not apply overvoltage as far as I can remember, nor did I short anything (on purpose) and I haven’t used big loads (motors, etc).
I haven’t used the yun in a while - the last thing i can remember is that I was trying to apply a newer linux image, which was kind of difficult because the newer boards had been released, and the old stuff was difficult to find.

I think I have the skills to replace the parts, but what I was wondering is, is it really those two, or is the real culprit some place before that?

Only one answer in a few days leads me to think it’s not a common problem anyways.

I’ll try to get the parts, which seems very difficult in amounts < 150, but won’t I immediately fry them as well if it’s something else?


And I'm a little confused now:

The schematics for the yun say it should be a MIC2005A-2, but the marking on the chip is FA51.

According to the datasheet ( ,page 3 ) FA51 would be a MIC2005A-1YM5

They differ by active high/active low. Doesn't that make a difference??

Cheers, Tobias

It certainly would make a difference.

There are a couple of different versions of the YUN so make you you dig out the schem for your version.

Yaeh, I consider it gone now, so it don't matter any more. :slightly_frowning_face:

While desoldering the USB port, I accidentaly cut one of the microscopic lines (the ones smaller than a needle tip) and I lack the skills to repair that.

Too much time invested already, economically speaking, but I really HATE throwing things away which could be repaired >:( ...

Thanks for the help anyways.