M4 noise problem (urgent)
I have a noise problem with my M4 ATX.When i start the computer after 4-5 seconds a noise starts coming from the speakers if i start the car the noise increases as i throotle up.
I know that you are going to say ground problem,thats what i thought at start,so i begun to checking everything until i get to M4.
I have for source an Alpine 9882 Ri,and bought the original alpine cable to make an aux in,all the test made with the cable on the air to check if it is ok.I do not have an amplifier and i use for the speakers the amplifier of the alpine.
Thats what i did
1.checked all grounds-everything ok
2.removed the step down from 12v to 5v-Still have noise
3.all the power cables where from one side (drivers side) i even still removed them out and still have noise
4.made a half meter only ground cable and connected it to a clear spot to the drivers seat belt just in case that because i had 2 meter before ground cable
made noise.Still have noise
5.Removed all usb-still noise
Then i believed something was wrong with the computer so
1.removed everything from inside the computer (including the M4 ATX)and builted it outside the car in case that i had somewhere problem with my box grounding something that i couldnt see),nothing still the same noise.
I Even took 2 new cables from the battery took them outside the car and powered the M4 STILL THE SAME NOISE
so finally i removed the M4 ATX and connected its regular power supply AC powered.SUCCESS no parasite sound no more.
Another thing is that i noticed that when i took the ground cable out while the computer was working nothing stopped and continued to work with only the 12v cable connected.How is this possible?
I am working to eliminate this noise for about a week now i already have again half of the car disassembled,My nerves arent in a good situation,and i stopped just to write to you because if i continue thinking inside the car i WILL BREAK EVERYTHING INSIDE.
Does anyone had any similar problem?Any suggestions?Shall i return the M$ back or there is something that i can do?
Any advice would be helpfull.Thank you