Somebody requested me to repair an A4TECH HU-30 USB headset because it had been yanked off the port it was connected to and I said, "Sure bring it to me." I had the impression that it would be an easy fix and just reconnect like colored wires. It turned out that the chipset was attached to the plug instead of being embedded in the headset (with volume control) and the wires had been severed cleanly from the plug save for the Mic GND (M-). By process of elimination, M would be the red wire since it would be logical to sheath the microphone wires together and plain copper color is usually ground. I won't be removing the lacquer and tinning the wires until I know the correct orientation of the remaining wires. I am unable to find the schematic online for the proprietary wiring. If someone knows the correct pin-wire combination it would be a great time saver, if not, then this would be a trial and error process where I would trace the wires all the way back to the headset and mic (which I hate because these wires are atrociously thin). Thank you in advance.

Assumptions: M = red M- = copper RL- = copper-blue wire for speaker GND? R = blue? L = green?

5v and GND provided by the chip from the plug and PCB trace.