mtx amp not working

[rich dominguez]

mtx 7801 thunder amp d class humming loud noise weather rca signal input are hooked up or not need help what too repair

[Cal Weldon]

Moved to car audio. Troubleshooting is for forum related problems.

[Perry Babin]

Before you do anything...
* You MUST have the transistors clamped tightly to the heatsink when the amp is powered up.

* You should also insert a 15 amp fuse in the B+ line feeding the amp to help protect it if there is a problem (or accident) that causes excessive current draw.

* When probing any points with a meter or scope, be VERY careful not to let the probe slip and short between adjacent pins.



Do you have a multimeter or an oscilloscope?

Remove the top cover (screws on bottom around perimeter -- leave the ones in the center) and unplug the preamp board from the main board. Does it still make noise when powered up?