The R(ight) loudspeaker on my AKG-K99 headphones stopped working. I bought a replacement (x2) 'mini' loudspeaker.

After soldered the replacement the sound was "weird". No problem. I predicted that. Different loudspeakers, different sound! For that reason I already had the second sp-39 loudspeaker. So I went to solder the second replacement. But after I opened the L(eft) AKG loudspeaker, to my suprise I saw more pads than the R(ight)!

BUT I have 3 (three) problems.

To my suprise the cables are 4 (four) instead of 3.

To my knowledge:

• 1 = common ground [Gold color ]
• 2 = positive (L channel) [Red color ]
• 3 = positive (R channel) [Red color ]

(end of TRS story) Problem #1

• 4 = WTF? (What's The Fing?) [Green color]

I made some continuity test's. (I de-soldered the monacor / replacement before testing - more for that later)

Problem #2. Continuity partners (check picture for numbers: AKG-L loudspeaker connection ): 1 [green] + 2 [gold] (!), 3 [red] + 4 [red] (!!). How's that possible?

Problem #3. Continuity partners mini jack (TRS) vs cables (factory soldering). (Check TRS connection for numbers) 1 [Sleeve] with Green AND gold (!). 2 [Ring] with BOTH reds (!!), 3 [Tip] with Green AND Gold (!!!).

Also to my suprise #2 Monacor has 4 tabs probably to cover the 'host' situation L. I was expecting 2 pads per loudspeaker but I have 4. I have some lack of knowledge here. How to solder the monacor as host (L) and as client (R)?

This is my soldering (weird sound - more loud, but adjusting the balance is not helpful) My monacor soldering for R channel

Problem #4: In monacor ALL pads have continuity (!!!!).

Simiral threads - but for some reason didn't help. Sorry. Headphone wire color coding Fixing headphone jack