Re: openbrick destroyed -- can it be fixed?

On Sat, 2004-06-26 at 03:44, Joey Hess wrote:
> I accidentially plugged 12 volts into my original openbrick, which takes
> iirc, 5. There was a minor sparc, and it buzzed in what seemed like
> morse code. Now if I plug in the right power, the front and back LEDs
> come on, even if the power switch is turned off. And it doesn't boot at
> all. I'd like to try to fix it, anyone know what capacitor or whatever
> is likely to have been fried by the excess voltage?

This happened to someonelse 2 years ago, let me see if I can dig out the
mails (were on this list):

yep. here come the relevant excerpts: read em through to the end for
salvation....

------------------------8<----------------8<------------------

On 2002.11.01 15:33 Niklaus Giger wrote:
> Hi,
> 
> In order to clean up my mess of cable I rearranged everything and
> managed to to plug in a 12V cable for my netgear switch into the
> 5V input of the OpenBrick, where it stayed for a couple of second
> until I realized my error.
> 

<SNIP>

> 
> What can I do? Is it possible to replace just one defective piece?
> 

If you are lucky you just burned one of the voltage 
regulators, three-pin components that you could replace
with a soldering iron and a bit of dexterity.  Does any
component look obviously grilled?

R,
        Luuk


------------------------8<----------8<------------------

On 2002.11.01 20:42 Niklaus Giger wrote:

> No, I do not see any burned parts. I do not mind soldering big enough
parts, 
> but I do not want to touch SMD personally. Also I have some collegues
at work 
> which have good equipement to solder.


You could try to measure if there is a voltage after the regulators to
identify
which one /could/ be broken.  They are quite easy to recognize, there is
one near
the tv-out connector, labelled AMS1085CD, and one near the cpu, labelled
1084MC
you can find datasheets on 

        http://www.advanced-monolithic.com/voltage_regulators_spec_s.html

It's a wild guess, but you might be lucky.  Another potential candidate
for a first victim is the elco rigth after the power inlet.  in my brick
that looks like it's only dimensioned for 10v, although it is difficult
to read.

good luck,
        Luuk

-------------------------8<-------------------8<----------------------
Hi Niklaus,

Thanks for sharing this knowledge with us:

On 2002.12.04 23:05 Niklaus Giger wrote:
> Hi
> 
> As some of few remembered very well I am the guy which tried to apply
> 12 V to the 5V inlet of the OpenBrick. 
> 
> Thanks to the tip of Luuk van Dijk and the help of some friends at
> work we  managed to get hold to a IRU1050 voltage regulator (the were
not in
> stock, which delayed the whole affair a little bit) and to replace the
> defective one. 
> 

Thanks to this experiment, now we know that the IRU1050 
is the weakest link.  Looking up the specs
(google:IRU1050+specifications), 
we find under absolute maximum ratings: 7 volts.
I am assuming it is directly fed from the 5.1 volt input, so 
I'd keep that 7V as the maximum to power the OpenBrick with.

R,
        L.