Gameboy DMG-01 broken L channel

[gorgyrip]

The Right channel is working fine. On the LEFT channel i can only hear very faded the gameboy logo and after that the Left channel outputs some noise, and the noise has the right volume. The same happens for the internal speaker and also for the headphones.
I've attached a schematic for the sound I found online.
Here are the things I tried:
1. I made sure the small sound board is working. I replaced the 2 x 100uf caps. I even swapped channels to make sure the board is working.
2. I checked the volume pot, I even bypass it with wires. So now I have full volume.
3. I checked the 2 caps and 2 resistors on the CPU sound output. They are good. I even swapped them between channel and no difference.
4. Now the interesting part. If I remove C4 (cutting the LEFT channel), the right channel is still working fine. But if I cut the Right channel, the Left channel has only noise (no longer the gameboy logo sound followed by noise).
5. I swapped channels before going inside the amp just to make sure the amp is working. The original left channel still has the same problem.
6. At this moment I believed there's something wrong with the CPU. So I replaced the CPU (from an untested gameboy). SAME PROBLEM.

Am I missing something or I am just unlucky and have 2 damaged CPUs?

 

[Tokimemofan]

Try lifting both pins on the cpu and with a game running connect them with a needle 1 at a time to the working channel, I wouldn’t be surprised if there is a bad trace.

 

[gorgyrip]

I've tried to swap the pins on the cpu. The pin for the Left channel still has only noise in zelda.
SOLVED. Shortcut between RD and L channel.