Just picked up a GK 1001RB II. Great deal... good seller. Local CL deal. Amp sounds nice.. no apparent issues. Took the top off just to see if it had anything done to it. Looks clean. Wanted to see if the fan circuit works so I left the top off and turned it on. ALL volume down..no signal. Fan came on in about 15 minutes. I've let it run for about 2hrs..again volume down, no signal. The fan has yet to turn off. My question is: after the heat sink or wherever the heat sensor is cools down shouldn't the fan shut off? I understand there's a lot of output devices on that heatsink...so maybe that's it.... ??? The amp sounds great but I'm wondering if the fan circuit is working properly. Ideas?