my buzz fix method
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Hi, Here is my attempt http://anyotherkey.googlepages.com/c AFAIK I made a few mistakes: 1 I could have used a smaller sized 100uF cap 2 I could have used thinner wire, I picked up the wrong spool and didn't realise 3 I shouldn't have tried to open a solder bridge on a 0402 component with a relatively large iron. I'm looking into the low volume of my voice on calls, I've only read up briefly on what could be the cause. I can't be certain it wasn't always so low! I am looking through the posts to figure this out from other peoples experiences. ![[FSF Associate
Member]](http://www.geocities.com/aclearn/getButton.png){kind=small} _______________________________________________ hardware mailing list [hidden email] http://lists.openmoko.org/mailman/listinfo/hardware |
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Am Fr 27. März 2009 schrieb Anthony Clearn:
> Hi, > Here is my attempt http://anyotherkey.googlepages.com/c > > AFAIK I made a few mistakes: > > 1 I could have used a smaller sized 100uF cap > > 2 I could have used thinner wire, I picked up the wrong spool and didn't realise > > 3 I shouldn't have tried to open a solder bridge on a 0402 component with a relatively large iron. > > I'm looking into the low volume of my voice on calls, I've only read up briefly on what could be the cause. I can't be certadinin it wasn't always so low! I am looking through the posts to figure this out from other peoples experiences. Hey Anthony muchas gracias for this really cool photo footage. Close to real live. It's been all the same when I started to try and do that. Regarding your low volume: did you check R4303? (It's the one below the two NC pads and right side to C4303, the one you borked and replaced. It's clearly mentioned in my SOP paper) R4303 is not mentioned in your story if I didn't miss anything. Usually it's 0R and it's amazing you get *any* signal at all from mic if you haven't replaced it by a ~2k2k (probably anything between 400Ohms and 3k will do, though I learnt by your report even a 0R will do at least partially :D ). Please keep on reporting this way, and don't hesitate to ask me for whatever kinda help you might need. I have a few spare devices for emergencies ;-) Your report is considered *very* encouraging by me. It shows how much you can deviate from SOP recommendations and still you get better results than MP device. Also it shows everybody is encountering some sort of same problems when doing this first time, and there's a way to recover from those. a heartly cheers jOERG _______________________________________________ hardware mailing list [hidden email] http://lists.openmoko.org/mailman/listinfo/hardware |
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Some javascript/style in this post has been disabled (why?)
Hi Joerg, thanks for the reply.
You must have missed this bit (before the first photo)
"I probed R4303 and found it was 2k2Ω"
my phone was manufactured on 20080821.
From: Joerg Reisenweber <[hidden email]> To: [hidden email] Cc: Anthony Clearn <[hidden email]>; [hidden email] Sent: Friday, 27 March, 2009 2:34:00 Subject: Re: my buzz fix method Am Fr 27. März 2009 schrieb Anthony Clearn: > Hi, > Here is my attempt http://anyotherkey.googlepages.com/c > > AFAIK I made a few mistakes: > > 1 I could have used a smaller sized 100uF cap > > 2 I could have used thinner wire, I picked up the wrong spool and didn't realise > > 3 I shouldn't have tried to open a solder bridge on a 0402 component with a relatively large iron. > > I'm looking into the low volume of my voice on calls, I've only read up briefly on what could be the cause. I can't be certadinin it wasn't always so low! I am looking through the posts to figure this out from other peoples experiences. Hey Anthony muchas gracias for this really cool photo footage. Close to real live. It's been all the same when I started to try and do that. Regarding your low volume: did you check R4303? (It's the one below the two NC pads and right side to C4303, the one you borked and replaced. It's clearly mentioned in my SOP paper) R4303 is not mentioned in your story if I didn't miss anything. Usually it's 0R and it's amazing you get *any* signal at all from mic if you haven't replaced it by a ~2k2k (probably anything between 400Ohms and 3k will do, though I learnt by your report even a 0R will do at least partially :D ). Please keep on reporting this way, and don't hesitate to ask me for whatever kinda help you might need. I have a few spare devices for emergencies ;-) Your report is considered *very* encouraging by me. It shows how much you can deviate from SOP recommendations and still you get better results than MP device. Also it shows everybody is encountering some sort of same problems when doing this first time, and there's a way to recover from those. a heartly cheers jOERG _______________________________________________ hardware mailing list [hidden email] http://lists.openmoko.org/mailman/listinfo/hardware |
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In reply to this post
by Joerg Reisenweber
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Am So 5. April 2009 schrieb Rask Ingemann Lambertsen:
> On Fri, Mar 27, 2009 at 03:34:00AM +0100, Joerg Reisenweber wrote: > > > Regarding your low volume: did you check R4303? (It's the one below the two NC > > pads and right side to C4303, the one you borked and replaced. It's clearly > > mentioned in my SOP paper) R4303 is not mentioned in your story if I didn't > > miss anything. Usually it's 0R and it's amazing you get *any* signal at all > > from mic if you haven't replaced it by a ~2k2k (probably anything between > > 400Ohms and 3k will do, though I learnt by your report even a 0R will do at > > least partially :D ). > > Joerg, could you clarify the significance of R4303 a bit? For example, > how would I tell if it has 2.2 kOhms or 0 Ohms without measuring it (on a > device without the buzz fix as well as with the buzz fix)? Probing is the *only* way you can tell afaik. We are basically grounding upper end of mic with a huge capacitor (AC), so we need some R >>0Ohms on the lower end of mic to get some signal at all. > > The 100 uF capacitor is just the C4306 which isn't installed by default, > right? Without checking for correctness of #4306 basically yes. > > MICBIAS is also supplied to the headset mic (location 44xx). Would it do > any good to add a 100 uF capacitor somewhere in that area too? Nope, for a number of reasons it won't work, just break function of hs-mic completely. See explanation some lines above. HS-Mic is singlen-ended (lower pin connected to GND) /j _______________________________________________ hardware mailing list [hidden email] http://lists.openmoko.org/mailman/listinfo/hardware |
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Am Di 7. April 2009 schrieb Rask Ingemann Lambertsen:
> On Mon, Apr 06, 2009 at 12:59:21PM +0100, Joerg Reisenweber wrote: > > Am So 5. April 2009 schrieb Rask Ingemann Lambertsen: > > > > > Joerg, could you clarify the significance of R4303 a bit? For example, > > > how would I tell if it has 2.2 kOhms or 0 Ohms without measuring it (on a > > > device without the buzz fix as well as with the buzz fix)? > > > > Probing is the *only* way you can tell afaik. > > We are basically grounding upper end of mic with a huge capacitor (AC), so we > > need some R >>0Ohms on the lower end of mic to get some signal at all. > > I see. So > 1) on an unfixed device, we'll get away with 0R R4303 with no perceptible > loss of mic volume? > 2) preferably, we'd put the 100 uF cap on MICBIAS, i.e. before the 2k2 > resistors R4305 and R4408 and parallel to 4U7 C3015, so that we don't fix > the voltage of one of the mic terminals? Of course this has been tested, but source impedance of the MICBIAS voltage regulator which is also creating the ripple (totem pole output it seems) is so low we needed a 860uF and even then there was buzz left. To form a decent lowpass filter for ripple we need to have some R between C and MICBIAS output. /joerg _______________________________________________ hardware mailing list [hidden email] http://lists.openmoko.org/mailman/listinfo/hardware |
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