Sony cdx m610 resets itself at half volume

You have a shorted speaker or speaker wire. If a wire is touching metal lightly it may not have full continuity (short) and will work until more voltage (volume) is sent to the speaker and causes the short. Disconnect all speakers at the radio then turn the unit back on. Turn up the volume and see if it cuts out. If it stays on, re-connect speakers one at a time and test. Once you find the problem speaker, disconnect the wire at the speaker then test again. This will eliminate the speaker itself as the problem. Test again. If it still shorts, trace the wire from dash to speaker and look for a cut in the sheathing exposing the wire. Repair or replace the wire and you should be good to go. If the unit cuts out with all speakers disconnected, the problem is internal and will need to be serviced. Before you repair/ or replace the unit either check all the wiring and the speakers or have someone do it for you so it does not give you a repeat performance. Hope this helps.