I have it soldered as this

1. R - to right rca
2. W - to left rca
3. W - to left 1/8
4. R- to right 1/8
5. G - to ground

(R) red, (W) white, (G) green.

The green ground daisy chains from the rca to the 1/8 then to the pcb.

As I said it all works until I plug in the display ribbon. Guess I might have to strip it all back and start again. Great fun all the same.

Re-solder everything.

Your explanation is a bit confusing but I am going to guess that you did this post pot.  Your pot is probably dirty.  I had a similar issue and just redid mine pre pot and the issue went away.

I've recently pro sound modded my Gameboy DMG-01 both the 1/8 and RCA modifications.

I have an issue and was wondering if anyone has come across this problem.

I thought it was my soldering technique at first but after resoldering the connections and testing, I realised that when I plug in the ribbon cable for screen, the sound cuts out on the left channel on everything but the standard headphone jack where the level drop very slightly.

I aslo shielded my soldering with electricians tape just to make sure I wasn't bridging connections somewhere.

All I can think that may be occuring is a power drop?

I'm a newby to modding but I want to do more. Already got another DMG from ebay.
I love LSDJ and have a AdvanceSP but really want to use a DMG for the Sound quality when recording.

Any ideas to what could be wrong, can anyone supply a solution to my problem?