Monday, 21 December 2009

The Puppy Breathes Again

I was talking about ARM stuff on an IRC channel and got interested in playing with my BeagleBoard(s) again. I remembered there was a hardware issue that caused the UHCI port to fail pretty regularly and looked up to see if the designers had found a fix.

Fortunately they had.

Subject: [beagleboard] Re: USB EHCI problems
From: Gerald Coley (
Date: Nov 9, 2009 5:57:18 am
List: com.googlegroups.beagleboard

This issue is due to be fixed with on REV C4. It is not clear that it can be fixed on all Rev C3 boards. You are free to try an RMA, but their is no guaranty that it can be fixed. What will be done there is the soldering of the 20uf CAP across C97 and then they will run the board for a couple of days to see how well it works.


So, at 3am on a Saturday morning I went looking for parts. I was feeling a bit apprehensive about soldering on such a tiny part, but I didn't really feel like sending it in either. I found a 22uF electrolytic cap on an old motherboard on which all the green caps blew which fit the bill and fit the tiny spot on the board. I worked out which pin was connected to the ground rail and gave it a shot.

So after that I had to re-setup a booting image - previous ones had been wiped to use my digital camera, and a HDD was wiped to transfer tv shows. Setting it up is a bit messy but didn't take too long. Once I got it setup I had it playing video and internet radio and left it running overnight (well over-day, it was about 6am by now).

And it's been up since.

Nice one - before I was lucky to get an hour, and copying some video files across the network would've almost certainly killed it. Well thanks to the BeagleBoard guys for finding a fix. After reading about the technical specs of the OMAP chip I'm almost surprised the thing works, electronics is such a fiddly thing, compared to software where at least 0 always means 0 and 1 always means 1.

Now, to find something to do with it ...


Bharath said...

Cool! This bothered me so much!
I thought i was the only one with this prob...
one question:
Did you remove the C97 Capacitor and put 22uF?

NotZed said...

It was mentioned on the newsgroup quite a bit, but it was difficult to find. Although I see it still keeps coming up.

I just soldered straight over it - I don't have the eyesight, steady hands, or equipment to do much else. Actually the existing cap helped provide some mechanical support, but it isn't very good, the right part would probably be better, or send it back to get it done properly.

It's been really rock-steady since, no problems at all. Now if only I could get my code to work so easily ...

Bharath said...

Thanks a lot NOTZED...

I soldered 22uF capacitor on top of the C97 capacitor in my C2 board & works well.
The random resets have stopped.

You might want to see:

where Gerarld, the PCB designer of BB, mentions about the noise issue...