Random shutting down

This answer is generic to most sound system amplifiers:

Check to see if the speakers are too low impedance for your unit. For example, if you have 4 ohm speakers and the system is rated for 8 ohms only, it can go in to protect mode (shut-down). If you are running 2 sets of speakers at the same time, and the total load impedance is equal to less than the spec of the amplifier, this can cause a safety shutdown.

The output stage power devices (transistors or IC's) can be going over temperature. This you will not be able to feely with your hand unless it was extremely severe.

It is possible that there is a component(s) that have become thermo sensitive, and when reaching normal operation they go out of specs. It is also possible that there is a cold solder connection and with thermo expansion from the normal increase of temperature, there is a loss of contact and the amplifier goes in to protection.

One other thing I have seen, is where the customer uses the amplifier excessively loud where there is some distortion. This causes some clipping in the sound. Sometimes the distortion can be very low to the point where to the listener the sound appears to be clean sounding. After some time, the amplifier will be triggered in to protection. If this is the case, you need a higher powered amplifier, or more efficient speakers, and or both.

You should get this checked if your connections to the speakers are compliant to the spec of the amplifier.

Jerry G.