[Yoga Flame]

The sound on one driver cuts out completely if I tap it with my finger hard enough. And tapping it again brings the sound back. I did a quick check on the driver's wire terminals and they do not appear to be shorted. The wiring looks sound too. My theory at the moment is there is a small particle inside somewhere that jams up the moving parts.
 
I'd appreciate any advice from you experienced Grado modders. Is this something I can fix?

 

[Yoga Flame]

Or have I just been sloppy in checking the wiring? I'll even try resoldering this if anyone thinks the "small particle" theory is unlikely.
 

 

[FallenAngel]

Very unlikely theory, resolder away.

 

[nikongod]

What does the multimeter say when probing the plug end of the headphones and wiggling the cable about? 
 
Your cable is bad. I'm more than 97.531% sure. Sorry to be the bearer of bad news.

 

[Yoga Flame]

Thanks guys. I measured the resistance and the good side was fixed at around 33Ω while the bad side went as high as 90Ω, but varying each time I tapped the driver with my fingers. Jiggling the cable seems not to change anything though.
 
FYI I got these from someone else in this state. I had recabled them with new starquad figuring there was a short or bad solder, or even a bad wire. Will resolder the bad side again and hopefully get it right this time.

 

[Yoga Flame]

So I measured across the blobs of solder directly and got the same fluctuating ohm values as with the plug end point. Now I'm a little nervous that the tiny wires underneath might be in in an extremely delicate state. Any final tips before I desolder? Will probably put this off till tomorrow.
 

 

[FallenAngel]

Cold joint on red wire.

 

[Yoga Flame]

Many thanks! That comes as a bit of a relief to me actually.

 

[Yoga Flame]

Something else seems to be going on here. I reflowed the red wire solder with helping hands and lots of flux. No improvement. Reflowed the black wire solder too. But still no improvement. Cleaned up the gunk with isopropyl alcohol also.
 
I measured the resistance from the plug tip to the square solder pad things on the driver at 0.6Ω each. So the wiring looks to be okay. But when I measure between the two square pads, that's when the high resistance comes in.
 
I suppose the next step is to desolder it completely. A solder sucker should be able to handle those large blobs easily I think. Any precautions I need to take? Any suggestions on what to do after that?
 
Once again I fear there might be a little wire underneath on the edge of disintegration. Can't think of anything else that would cause these high resistance readings.

 

[Yoga Flame]

Desoldered. The little wires look all right to me. Any ideas on why this Grado driver measures at 90Ω (and sometimes more)? Is this the end of the road?
 

 

 

[FallenAngel]

Burned driver?

 

[nikongod]

Intermittent wire in the voice coil? 
 
Its just another way of saying what FallenAngel said. 

 

[QRomo]

 

I have a tangentially related question: how long is it safe to leave a headphone driver connected to a DMM in resistance mode? My meter applies 2.5V DC, so that would be just under 0.2W in 32 ohms. Seems pretty high.
 
Not that I think this has anything to do with Yoga Flame's issue, just wondering in case I ever have to diagnose a misbehaving phone.
​

 

[nikongod]

You need to measure the output current of the meter to tell how bad it is for your headphones. The voltage into the 10Mohms of another meter is meaningless when it can only put out 0.000001A
 
Hook the meter set up to measure resistance up to another meter set to measure current. Use current into the resistance to figure out power. 

 

[QRomo]

Yeah, I should have read the specs on my meter more carefully before posting. It puts out a maximum of 1.7mA, so no real danger.