Quest Qmotion L600a peak light!! stuck

Hey guys, I have a Quest Qmotion L600a system and I was curious if anyone knows this system?
When I run music into it the sub works and the right satellite works but the left side is a bit quieter
and the limit light is constant red even when you have no signal running to it and no speaker attached.
It would be a massive help to narrow it down to either the output board or the pre amp board.
I'm thinking the pre amp board???

Cheers


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