I have a kicker zr120 2channel amp. It powers up but it is very distorted at any volume and any gain level. It has the interchangeable modules I have tried two different ones to rule that out. I have a multi meter but not much else. Any help would be appreciated.
If you haven't done so already, confirm that the ±15 and ±25 v are present on the 10 pin header. Black probe on one of the non-bridging speaker terminals. Don't let the probe slip and short between header pins.
You can bypass the module by jumping the two outer pins on either side. I did this on my zr1000 and one side only played highs and had intermittent cutting\distortion but when I reflowed solder on the 20 points at the base of thecrossover holder it returned to normal.