PDA

View Full Version : That was a very stupid thing to do.



tobyjug
2009-02-03, 05:01
Whilst configuring my squeezebox 2 to automatically turn on my amp and select the CD option (IR blaster), I accidently connected a 9V supply to the 3.5mm socket. Hence the title. The Squeezebox turned itself on and there was a strong smell of fried semiconductor. The analogue outputs are no longer working but the digital out is. My question is: I am OK with a soldering iron so what have I most likey fried? Help!

st2000
2009-02-03, 07:35
tobyjug wrote:
> Whilst configuring my squeezebox 2 to automatically turn on my amp and
> select the CD option (IR blaster), I accidently connected a 9V supply
> to the 3.5mm socket. Hence the title. The Squeezebox turned itself on
> and there was a strong smell of fried semiconductor. The analogue
> outputs are no longer working but the digital out is. My question is: I
> am OK with a soldering iron so what have I most likey fried? Help!

Wow, the processor, network interface, display and spdif output still
all work?! I think you are lucky.

As far as I can tell no schematics are available. (This part of the
slimdevices design is not open source like the server.) However I've
noticed that "seanadams" ( profile:
http://forums.slimdevices.com/member.php?u=3) said this: "The full
schematics have never been released. However, I'm usually happy to
answer specific questions." in this forum:
http://forums.slimdevices.com/showthread.php?t=31187.

Without the schematics I think people can only guess at what happened.
If you back drove 3V or 5V logic with 9V you might have presented 9V to
everything. Hence why I'm surprised anything works. But I would have
guessed the logic (i.e. processor) would have failed before the analog
output. Generally, the analog output is isolated to ensure digital
noise does not creep into the signal.

Any ways, on the hunch it might be easier to build what doesn't work
external to the SB instead of repairing it, I came across this DAC project:

Go here:
http://www.ezdiyaudio.com/
Find this project:
Project 2: ezDAC

There are even pictures using the SB as a source.


....have fun

seanadams
2009-02-03, 08:33
The whole DAC/RCA/headphone side of the system is pretty well partitioned and runs on separate power regulators from the rest of it, so actually I'm not too surprised that the CPU etc was unaffected.

But that doesn't mean it's easy to fix - there are about six active components that could have been cooked - DAC, op amp, headphone amp, and three regulators. If you look inside can you tell visually what's fried?

st2000
2009-02-03, 09:28
seanadams wrote:
> The whole DAC/RCA/headphone side of the system is pretty well
> partitioned and runs on separate power regulators from the rest of it,
> so actually I'm not too surprised that the CPU etc was unaffected.
>
> But that doesn't mean it's easy to fix - there are about six active
> components that could have been cooked - DAC, op amp, headphone amp,
> and three regulators. If you look inside can you tell visually what's
> fried?

I guess I'm confused here. (I don't have an SB w/an IR output.) Did
you plug a 9 volt power supply into the IR output or the headphone output?

Also, if you open it up, pay attention to the static electricity. This
time of year (cold-n-dry (on the north side of the world)) it wouldn't
take much to put it all out of working order.

tobyjug
2009-02-03, 09:43
Just opened up the box and the 14pin dil package U11 looks fried. I can't read all the text on it but it ends in "17K"

funkstar
2009-02-03, 10:33
I guess I'm confused here. (I don't have an SB w/an IR output.) Did you plug a 9 volt power supply into the IR output or the headphone output?
The headphone output can be used as an IR output. It's also refered to as the Geek Port.

seanadams
2009-02-03, 11:03
Just opened up the box and the 14pin dil package U11 looks fried. I can't read all the text on it but it ends in "17K"

that part is just a CMOS switch - very common: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-14854-1-ND

However if the RCA outputs are not working then it probably means the DAC is fried too. that's U1, PCM1748KE. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PCM1748KE-ND

Measure the voltage across C61 - you should get 5V. If not, then it means the 5v regulator (U12) is cooked. http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-11118-1-ND

tobyjug
2009-02-03, 12:03
There is 5V (well 4.9) accross C61 so at least somethings OK. I will replace the other two devices and see what happens. Thanks for your help.

tobyjug
2009-02-06, 14:15
Well that wasn't easy. First real attempt at soldering SM components. Wasn't pretty. But it's working again, and it seems to sound better than it did before. Just had to change the analogue switch and DAC. Thanks for all your help guys.

seanadams
2009-02-06, 14:16
very good! :)

pfarrell
2009-02-06, 14:42
seanadams wrote:
>> Well that wasn't easy. First real attempt at soldering SM components.
>> Wasn't pretty. But it's working again, and it seems to sound better
>> than it did before. Just had to change the analogue switch and DAC.
>> Thanks for all your help guys.
>
> very good! :)

And people sometimes wonder why I'm in the tank for SlimDevices.
Here is the founder of the company helping a guy solder surface mount
components.

None of that "no user servicable parts inside" story.

Sean is the best.

I sure hope the corporate folks at Logitech realize what a great company
they joined.

--
Pat Farrell
http://www.pfarrell.com/

toby10
2009-02-06, 15:46
seanadams wrote:
>> Well that wasn't easy. First real attempt at soldering SM components.
>> Wasn't pretty. But it's working again, and it seems to sound better
>> than it did before. Just had to change the analogue switch and DAC.
>> Thanks for all your help guys.
>
> very good! :)

And people sometimes wonder why I'm in the tank for SlimDevices.
Here is the founder of the company helping a guy solder surface mount
components.

None of that "no user servicable parts inside" story.

Sean is the best.

I sure hope the corporate folks at Logitech realize what a great company
they joined.

--
Pat Farrell
http://www.pfarrell.com/

I'll bet Sean is a "solder" person himself and obviously likes to tinker, so he admires and encourages those who share (or are at least willing to try) his interests.

And you are right, let's hope Logitech Corp. realizes the gem they have and leaves SD alone to do their thing!

An example of a big biz buyout gone wrong (interfering): In my lovely home town of Cleveland Ohio a motor-head grease monkey into weekend car racing didn't like the performance of the motor gaskets on the market, so he made his own. Then he started to sell them to his fellow weekend racers, grew the biz hiring his gear-head buddies who knew and understood their market. This became Mr. Gasket, a big operation.

Along comes W.R. Grace Co., a HUGE conglomerate, buys out the original owners, fires all of the gear-heads cuz they "don't fit our corporate structure" and replaced them with MBA grads. In short order, these MBA bean counters ran the biz into the ground cuz they knew nothing of their market/customer.

Eventually the original owner bought back the company (at a fraction of what he sold it for), fired the MBA's, rehired many of his old gear-head buddies, built the biz back up.

Solder-heads, gear-heads, FLAC-heads, whatever.....don't let those MBA's run your biz cuz they don't know your customer. :)

funkstar
2009-02-08, 10:48
I'll bet Sean is a "solder" person himself and obviously likes to tinker, so he admires and encourages those who share (or are at least willing to try) his interests.
There are still photos :)

http://web.archive.org/web/20011022193003/www.slimdevices.com/pics.cgi?assembly

Dogberry2
2009-02-08, 16:25
Sean & the Slim crew rock!

eq72521
2009-02-11, 14:58
This thread is pretty awesome. Interesting that the beer-containing image is missing on that archived page.

tobyjug
2009-02-12, 05:34
Flushed with the success of replacing the DAC, I have just upgaded the opamp to a AD8260. Sounds even better! Just reading up about capacitors...

Phil Leigh
2009-02-12, 06:22
Flushed with the success of replacing the DAC, I have just upgaded the opamp to a AD8260. Sounds even better! Just reading up about capacitors...

Welcome to Hell :-)

iPhone
2009-02-12, 09:44
There are still photos :)

http://web.archive.org/web/20011022193003/www.slimdevices.com/pics.cgi?assembly

Hey Funkstar,

When I pull up the link the pic with Sean is the only one missing. Is it there for you or anybody else?

funkstar
2009-02-12, 09:52
Hey Funkstar,

When I pull up the link the pic with Sean is the only one missing. Is it there for you or anybody else?
yeah that was broken for me too, but i put it down to archive.org being painfully slow and unreliable.