I recently got a Aguilar GS212 from a pawn shop, and they gave me a day to take it home and try it out. everything seems good, and i really like the cab, but the tweeter seems to be working intermittently. For example, (with tweeter on 100%) it will work for 20 minutes, and then stop, and then come back on all of the sudden randomly. What would be causing this? I checked all the wiring and the contacts are solid. Could it be the crossover? And when the tweeter is on, it seems rather hissy, but i read that might be normal.