Rockbox Technical Forums

Third Party => Repairing and Upgrading Rockbox Capable Players => Topic started by: dreamlayers on March 24, 2008, 11:48:27 PM

Title: 5G iPod audio hardware appears dead
Post by: dreamlayers on March 24, 2008, 11:48:27 PM
I have a 5G iPod with some issue with the audio circuitry.  If I play something with Rockbox or the original firmware, the time doesn't move.   I also hear no sound whatsoever, including no noise.  With sensitive headphones and another iPod I hear clicks when putting the iPod to sleep, waking it up, or plugging in headphones.  The working iPod also wakes up if I plug in headphones.  Other than this the iPod functions perfectly.  Any suggestions for what could be wrong?  Is there any information on the circuitry out there, such as at least a rough circuit diagram?  I'm wondering if maybe the analog section receives power separately, and that is not being supplied.

Edit:  There is suspicious white residue in the power supply section of the motherboard, between the two Philips chips.  One tiny component seems especially affected, and there was a dot of green on a pin of one of the big chips, like corroded copper.  I don't think it can be an external leak and I think one of the two bigger nearby capacitors may have leaked.
Title: Re: 5G iPod audio hardware appears dead
Post by: zajacattack on March 25, 2008, 07:06:46 PM
I would recommend cleaning off as much gunk as possible without damaging the hardware.

Also, have you tested with more than one pair of headphones?
Title: Re: 5G iPod audio hardware appears dead
Post by: dreamlayers on March 25, 2008, 07:40:52 PM
Yes, stuff that got into it was the problem.  Something rather corrosive leaked in via the outer edge of the clickwheel at the next track button and some copper turned into oxide.  Pin 7 of the WM8758 (codec) was disconnected.  (I couldn't find a datasheet, but on the WM8978 datasheet the pin is LRC: DAC and ADC sample rate clock.)  The destruction was centered around a plated-through hole on that trace and another nearby hole that's all by itself was also corroded.  (I suspect the holes are more vulnerable because they're not coated by solder resist.) I decided to see what would happen if I fixed the severed trace without caring about the holes, and playback worked in Rockbox.
Title: Re: 5G iPod audio hardware appears dead
Post by: zajacattack on March 25, 2008, 07:42:27 PM
Glad you fixed it. You might also want to do something to keep it from corroding again (or at least from leaking).