Not sure the quality level of the meter you are using, but yes it can make a difference... most specifically in the OEM probes that come with affordable meters. For the longest time I refused to believe this until I finally bit the bullet and splurged on a better $25 pair of probes for the Fluke 179 my co-worker gave me. Up to that point, with cheap probes (even with the Fluke) I was getting all kinds of "off" measurements that weren't making sense and driving me nuts and into a tail-spin.
Set your meter to read Ohms and measure:
TIP-Sleeve should be ~31.5 Ohms
RING -Sleeve should be ~31.5 Ohms
TIP-RING should be ~63 Ohms, (its the two coils in series, grounded together through the sleeve contact).
Since you've got the earcups open, and have cut the wires off the drivers... measure resistance across the solder pads on each driver, likewise it should be ~31.5 Ohms. If it doesn't then you have an open circuit somewhere inside the driver. Either the solder pad(s) have become disconnected from the tiny lead wires, the lead wires have broken, or the voice coil itself has developed an open circuit. I don't know if there is an easy way to repair either of the 3 scenarios. I had a KSC 75 driver where the solder pad became disconnected from the lead in wire. I tried to re-flow solder and re-connect it, but failed miserably in that the heat from the flowing solder melted and disintegrated (for lack of a better term) the really tiny lead wire.
I have heard about loudspeaker voice coil repairs that involved "unwinding" a coil or two and using that newly exposed length to bridge over and re-attach to the lead wires. I have never heard about anyone successfully doing this with a headphone voice coil however. I tried it on a busted HD580 driver... with no luck at all.
At any rate heres some pics of Grado drivers... You can see the lead wires under the diaphragm material.
Edited by kramer5150 - 5/10/14 at 1:37pm