Express Headphone Issue

[crazedbinary]

Whats up.

I recently did a recap using a SMD kit from console 5.  Everything is back and running well except the headphones.  Loud buzzing and only one sound channel it seems.  I have two expresses right now and I was measuring caps and checking traces.  ESR and everything look good with the new caps. 

There is a small ceramic capacitor/resistor?? L105 that looks like it may be bad by the headphone jack.  I cant measure ESR from it.  Anyone know if this could cause the issue and if so what a good replacement is?  Pic Attached.

[NichlasEk]

I would guss L105 is a small inductor. It should messure small to no resistance. If you dont get continuity over it. It might need replacing. You could try bridging it for a short test if you dare.

[crazedbinary]

That is correct.  There is not continuity over this inductor.  It tests fine on the other Express. 

Better pic attached for reference as well.

Any idea on how to source a replacement?



Thanks all!
Crazed

[NichlasEk]

Dont know where to find the info. But if you have a working
One. You could desolder and messure it, if yor DM can messure inductance? Might be 100mH or so.

[crazedbinary]

Unfortunately my Atlas can only do ESR/Cap measurement.  I was looking for an excuse to get an LCR meter anyway and went ahead and pulled the trigger on a DE-5000 to measure inductance etc... 

Do I need to desolder the working one to get an accurate reading?

[NichlasEk]

Nice! As loong as nothing is in parallell with it, i guss you could messure in circuit.

[Keith Courage]

If the traces for the caps in that area are good then usually the cuplrit for only one side of the sound working is a bad headphone jack. I've seen a lot of them damaged from people accidentally burning into the headphone jack with the soldering iron when trying to install new caps. Usually wrecks the internal connections in the headphone jack.

[crazedbinary]

Hi Keith -

I think the traces and jack are fine.  Pic attached for reference.  I desoldered it before attempting any work and it appears to be ok.  This particular inductor is testing differently on this Express compared to another.  I took reading from the "good one" still in circuit as I had to get it back to a friend.  Below are the readings I got.  Still learning inductance measuring so bear with my newbness.  Any help on sourcing this part would be great.

Inductance Measurements:
@1khz 1.1-1.5 mh usually 1.2-1.3
@10khz 1.28 mh
@100hz 1mh
@120hz 1mh

Resistance:
0.61 ohms

When using the "auto" part of the DE 5000 it identified the part as a resistor.  Not sure if that is correct.





Thanks - Crazed

[NichlasEk]

I see i made a misstake in a previos post. I meant 100uH not 100mH. Even 1mH seems high. Something like this might surfice http://www.ebay.com/itm/191674364470? I guess it could have blown if someone tried to connect it to big speakers instead of headphones? Keath?

[crazedbinary]

Sorry that was meant to read:

@1khz 1.1-1.5 uh usually 1.2-1.3
@10khz 1.28 uh
@100hz 1uh
@120hz 1uh

I think LOL.

[Keith Courage]

I'm just saying that if those headphone jacks get heated up in any way that one or both of the contacts that make the connection to the headphones moves out of place internally. To test this you can use a 3.5mm plug to bare wires and then use a multi-meter  to see if both sounds channels have a connection.

[crazedbinary]

OK I was able to get the part out of a working Express and below are the readings I found.  This was using my  DER EE DE-5000 LCR Meter in auto mode. 

1khz 0.562 ohms - resistor
10khz 0.805 ohms - resistor
100khz 1.350 uh - inductor (it picks it up as an inductor at 100khz)
100hz 0.56 ohms - resistor
120hz 0.57 ohms - resistor

I am trying to figure out is this is a resistor or an inductor and also what part to replace it with.  Is the eBay part mentioned earlier still a good bet?

Thanks all - Crazed

[crazedbinary]

Additionally, I just tested the working part in the Express with the headphone issue.  It solved the issue.  Now I just need help finding the replacement part.

Just as an FYI the broken inductor/resistor seemed to be broken in half when I desoldered it like it had cracked down the middle.

Thanks in advance - Crazed