asked
Quattro 10000 making strange noise(fans are off)
New or old install?
Totally disconnect the AC ipnut and output wiring (no switching off breakers is not the same thing) and switch it on is the sound still there?
Rest the system to factory (sometimes needs two or three resets) if it does not change one more thing to check....
If you are comfortable check the connections between all the boards are good. Particularly the ribbon ones.
If the unit still makes there noise ther is possibly a fault.
The other times I have heard a noise similar is with certain loads and long (perhaps not so great) cables to loads so the sine was was being messed with.
