Tuesday 18 March 2014

Fixing an Overheating USB Hub

So I've had a Belkin F5U237v1 USB 2.0 7-port powered hub for quite some time.  It's a pretty nice little hub to have; I especially like the top USB ports and the fact that I can charge USB devices from it without needing the computer turned on.

However, occasionally I've noticed it stops working entirely when I either (i) plug lots of stuff into it for a long time, or, (ii) when I'm doing something fairly intensive across it for a prolonged period of time (large file transfers to portable USB disks etc).

This hub has long since passed it's warranty and I didn't particularly feel like shelling out for a new one when this is fine 95% of the time.  However, I did notice that gets really hot to the touch just before it stops working.

Anyway, let's open it up:

The screws are under the four little feet on the base.  After they are out the entire thing just snaps apart without any problem.  It's made up of just one circuit board, which isn't secured to the case, so it's pretty hard to break anything.  The visor at the front, covering the LEDs, will fall out so make sure you don't lose it.

The majority of the heat seems to be coming from the power transistor on the left (labelled UTC 2N2955) with a smaller amount coming from the diagonally mounted chip on the right.  As the transistor heats up the amount of power it will be able to disipate will decrease - my guess is that the hub gets hot enough that the transistor can't cope with the load any more and it all stops working.

The internals don't look great for cooling.  It's an enclosed area with no airflow and a plastic shell acting as an insulator.  Letting it breathe a little bit should help.

Excuse the terrible drill work - I started trying to do this just using a masonry drill bit which didn't go terribly well - switched to a tile bit to do the slightly nicer holes.  Function over form anyway! The aim here is just to punch some holes in the plastic shell to let hot air out and, hopefully, cooler air in near the two hottest components.  This should keep the whole unit a little cooler.

Putting it all back together, remembering to put the LED visor in, it doesn't look too bad; even with my poor drilling work.  It's actually even less noticable in practice as I artificially lit the scene for the camera - this sits behind my monitor in the shade where the holes are virtually invisible.

Importantly, the hub runs a lot cooler to the touch which has hopefully solved my problem (at the very least it's not done it yet despite some fairly extensive testing).  If you do something like this on your own hub I imagine it'll void any warranty you might have.

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