Is there a Mackie authorized repair shop in your area ?
Possibly they could do a quick check or expedite the repair so your not without the item.
Even if they need a part, possibly they can order it and call you when it comes in so your not without the DL while they wait
for a part to come from Washington or overseas.
I would not open it myself in fear of voiding the warranty, plus I'm not as savvy as others here on the inner workings of these magic boxes.