fried rca's?

so I think my sub rca output is fried on my headunit. It is putting no bass out whatsoever. I checked the amp by plugging my ipod into it and it worked fine. This happened when I was hooking up an amp I just bought. I had a kicker zx300.1 and was now hooking up a Infinity 1600a 600 watt amp. I have 4guage cable. My subs started to freak out and my speakers all started to make a freaky whine noise. I shut it all off. Now when I try to turn it on again... I have no bass at all. Tested RCA's with a multi meter and there is nothing out of the sub pre outs. What causes an RCA to fry? My headunit is a kenwood ddx 6019.

Usually touching a power wire to the shield of an RCA cable makes the RCA fry. Get your meter and perform the test at the top of This Page. If the shield of your radio is not electrically connected to the chassis of your radio, you need to get it repaired or try the suggestion further down the page.

infinity amp strikes again! i used to have that problem sometimes when i used to work with infinity amps, but i have no idea what causes it. it would just happen randomly from time to time