all 4 Color FX LEDs not working on a DJM 800

Scenario is self explanatory 

one thing I will add, I bought a new batch of replacement LEDs, took the entire thing apart and while on "xmas tree mode" prodded the back of the PCB with the LEDS (both ways trial and error obviously)

so it's not the LEDs. I might need to take some photo's... you know the transparent plastic sheet that goes under both PCB's? there's a suspicious brown smudge above one area of transistors? near to where the 4 color fx buttons are. 

Any idea what might be causing the LEDs not to light? and it's not even a cosmetic problem this, I need those lights to know when I'm using a certain effect. 

edit: I bought the unit like this