Are you experiencing on a specific channel? Do you need help configuring an external effects loop ?
The mixer is lightweight (approx. 9.5 to 20.5 lbs depending on the specific model variation) and designed for easy transport in small vehicles. Digital Resources audio choice qm4 manual link
If you need specific wiring diagrams or component-level repair info, you might find similar architecture in manuals from related SoundTech or budget-pro brands: How to Set Up a Simple PA System 5 Feb 2013 — Are you experiencing on a specific channel