I just got a used WT800 from 2003 (I assume its an "A" model because of the round vents on top) to match with with my XLT410. It sounded amazing for about 5 minutes with my band and then the sound cut out completely. I look at the amp to find the EQ lights were out and the EQ clip light was solid for a few seconds then faded out. What have i done? Have I used the wrong output? I used the 1/4 inch output above the "L amp/HI" output. Im extremely bummed!! This was the best tone I've ever heard and now I dont know what's wrong. Any thoughts???