Re: Line In Not Responding

[Chris Barrett]

Here is the text dump I get from alsamixer.

On Tue, Apr 1, 2008 at 9:52 PM, Chris Barrett <[EMAIL PROTECTED]>
wrote:

> I just recently recieved my XO, and I love it.  But recently the mic and
> audio in jack refuse to respond.  The last time they worked was when I was
> using measure to read the voltages (or trying to anyways) of some batteries
> I had lying around.  I see that there is a max voltage, I'm worried I may
> have inadvertently fried the controller or some component of the system that
> the mic and audio in system rely on.
>
> I guess what I'm asking is what are my options?  I'd prefer to repair this
> myself, I'm relatively comfortable around soldering irons and have done some
> surface mount repairs and modifications before, but I'd like to know what to
> look for?  Would I need to replace the AD1888 IC
> or just a smaller component?
>
> Thanks in advance.
>
> Regards,
>
> Chris Barrett
> Cell 416-704-0268
> Office 416-469-8000
> [EMAIL PROTECTED]
> Suite 601a
> 235 Carlaw Avenue
> Toronto, Ontario
> Canada m4m 2s1
> www.barrett-architect.com




-- 
Regards,

Chris Barrett
Cell 416-704-0268
Office 416-469-8000
[EMAIL PROTECTED]
Suite 601a
235 Carlaw Avenue
Toronto, Ontario
Canada m4m 2s1
www.barrett-architect.com
Simple mixer control 'Master',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 22 [71%] [-13.50dB] [on]
  Front Right: Playback 22 [71%] [-13.50dB] [on]
Simple mixer control 'Master Mono',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 22 [71%] [-13.50dB] [on]
Simple mixer control 'Master Surround',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 0 [0%] [-46.50dB] [off]
  Front Right: Playback 0 [0%] [-46.50dB] [off]
Simple mixer control 'Headphone Jack Sense',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 28 [90%] [-4.50dB] [on]
  Front Right: Playback 28 [90%] [-4.50dB] [on]
Simple mixer control 'Surround',0
  Capabilities: pvolume pswitch
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 0 [0%] [-46.50dB] [off]
  Front Right: Playback 0 [0%] [-46.50dB] [off]
Simple mixer control 'Surround Jack Mode',0
  Capabilities: enum
  Items: 'Shared' 'Independent'
  Item0: 'Shared'
Simple mixer control 'Center',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 15
  Mono: Playback 0 [0%] [-46.50dB] [off]
Simple mixer control 'LFE',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined
  Playback channels: Mono
  Limits: Playback 0 - 15
  Mono: Playback 0 [0%] [-46.50dB] [off]
Simple mixer control 'Line',0
  Capabilities: pvolume pswitch cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'Line Jack Sense',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'CD',0
  Capabilities: pvolume pswitch cswitch cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Front Left: Playback 0 [0%] [-34.50dB] [off] Capture [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off] Capture [off]
Simple mixer control 'Mic',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined cswitch 
cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Mono
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono: Playback 0 [0%] [-34.50dB] [off]
  Front Left: Capture [on]
  Front Right: Capture [on]
Simple mixer control 'Mic Boost (+20dB)',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]
Simple mixer control 'Mic Select',0
  Capabilities: enum
  Items: 'Mic1' 'Mic2'
  Item0: 'Mic1'
Simple mixer control 'Video',0
  Capabilities: cswitch cswitch-exclusive
  Capture exclusive group: 0
  Capture channels: Front Left - Front Right
  Front Left: Capture [off]
  Front Right: Capture [off]
Simple mixer control 'Phone',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined cswitch 
cswitch-exclusive
  Capture exclusive group: 0
  Playback channels: Mono
  Capture channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono: Playback 0 [0%] [-34.50dB] [off]
  Front Left: Capture [off]
  Front Right: Cap

Re: Line In Not Responding

[Richard A. Smith]

Chris Barrett wrote:

> batteries I had lying around.  I see that there is a max voltage, I'm 
> worried I may have inadvertently fried the controller or some component 
> of the system that the mic and audio in system rely on. 

The line in is protected by a 5.1V zener and then there is a 1k resistor 
prior to the AD1888 Mic1 input.   So if you blew it up then you must 
have hit it pretty hard.

> I guess what I'm asking is what are my options?  I'd prefer to repair 
> this myself, I'm relatively comfortable around soldering irons and have 
> done some surface mount repairs and modifications before, but I'd like 
> to know what to look for?

1st in the signal path is L23 which is an ESD choke. The backside of 
that is where D13 (the 5.1V zener) connects to, then it goes to R25 
which is a 1k and then to C35 which is the AC coupling cap.  When you 
switch to DC coupling input ( ie measurement mode) C35 is shunted by a 
switch.  Then finally it goes to pin 21 of the AD1888 which is Mic1.

My suggestion is to connect up some sort of small signal AC input to the 
  Mic in and then look for that signal at each of the above components. 
  If you get to pin 21 then you must have blown up the input.  There is 
a 2nd unused Mic input on pin 22 which is routed out to TP 87.  You can 
try shorting the signal from C35 to TP 87 (or short pin 21 and 22) and 
then tweak your ALSA setup to use Mic2 rather than Mic1.

-- 
Richard Smith  <[EMAIL PROTECTED]>
One Laptop Per Child
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Re: Line In Not Responding

[Chris Barrett]

Hello all you fabulous people.  After much review and consulting an
electrical engineer who owed me a favor I was able to get into the XO and
figure out what had happened.  The Zener Diode D13 had indeed fried, I
removed it and the system works again.  I will replace it with something
suitable later, but I just thought I'd thank you all for your help.  It was
quite rewarding to open the thing up and see the hard work you all have put
into this machine, not only making it operate properly, but providing a
suitable platform for DIY repair.  I can honestly say that laymen such as
myself found the repair quite easy to undertake, and even learned a thing or
to by doing so.  Bravo!

It was an annoying-turned-rewarding experience, and I think your help made
it that way.  I am considering putting together a small guide for the Wiki
with the help of my friend just incase someone else comes across this
problem, but I am not sure as to how to illustrate the internal composition
without plagiarism of those schematics (which I assure you I will not do).
I will let you know if I manage to make some progress there.  I really just
want to give something back, as you all stuck your necks out trying to help.

Keep up the good work folks!

-Satisfied Donor.
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Re: Line In Not Responding

[Arjun Sarwal]

Chris

Thank you for the feedback and for sharing your experience.
I'm glad to know your XO is fine now.

Please do include what voltage you used (and approx how long if
possible) that made this happen.

many thanks
Arjun

2008/4/9 Chris Barrett <[EMAIL PROTECTED]>:
> Hello all you fabulous people.  After much review and consulting an
> electrical engineer who owed me a favor I was able to get into the XO and
> figure out what had happened.  The Zener Diode D13 had indeed fried, I
> removed it and the system works again.  I will replace it with something
> suitable later, but I just thought I'd thank you all for your help.  It was
> quite rewarding to open the thing up and see the hard work you all have put
> into this machine, not only making it operate properly, but providing a
> suitable platform for DIY repair.  I can honestly say that laymen such as
> myself found the repair quite easy to undertake, and even learned a thing or
> to by doing so.  Bravo!
>
> It was an annoying-turned-rewarding experience, and I think your help made
> it that way.  I am considering putting together a small guide for the Wiki
> with the help of my friend just incase someone else comes across this
> problem, but I am not sure as to how to illustrate the internal composition
> without plagiarism of those schematics (which I assure you I will not do).
> I will let you know if I manage to make some progress there.  I really just
> want to give something back, as you all stuck your necks out trying to help.
>
> Keep up the good work folks!
>
> -Satisfied Donor.
>
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