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Forum: µC & Digital Electronics iPod touch 1G not detecting headphones, broken transistor


von Lenny D. (le-do)


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Hi there,

I have an old iPod touch 1G 32GB which I opened recently to clean it 
thoroughly. After reassembling it would not detect plugging in and out 
the headphones anymore. This is a big problem since it does not display 
volume controls at the moment and is set rather quiet.

I reset the firmware, but as this didn't help I opened it again. 1 
component was evidently destroyed during reassembly. From an iFixit 
guide I was able to find out it used to be marked "1F":
http://www.ifixit.com/Guide/iPod+Touch+1st+Generation+Logic+Board+Replacement/632
(In Step 10, second picture, topright corner near headphone jack)
The internet says this must be a BC847BT SOT883 transistor. Now I'm 
reasonably new to SMD so I won't be able to replace it with the same 
model, but I found an old NPN SMD transistor in a Laser Pointer that I 
soldered in with some enamelled copper wire, pinouts according to the 
datasheets.

This has no effect so far, so I'm wondering what else I might do. I 
measured some voltages and on Collector, there are 2.99V, on Base 0.00V 
whether jack is plugged in or not, and on Emitter there are 1.79V even 
when no transistor was soldered in. The Jack connector has a contact 
opener connected to the Tip when unplugged and disconnected when jack is 
plugged in. This is directly connected to Base, I haven't measured any 
pullups or anything yet.

Does anyone have any ideas how the mechanism is supposed to work or what 
else I might do to save the poor ol' thing?
Cheers, Lenny

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