The volume control on this McIntosh MA6400 was not working when attempting to adjust it with the remote control. The volume control, at left below, is motorized. The motor driver is the long thin component at right below. The volume control worked fine manually, and I verified the motor was operational using a bench supply. I isolated the issue to the driver. You can see it blew a chunk of the package off the side of the part when it failed.
One channel’s output power was low and the channel was glitchy. I isolated the channel behavior to loose wires in a connector. These may have been knocked loose by some prior service work. I reworked the various issues and tested and verified the unit was performing well. If your McIntosh MA6400 volume control is not working with the remote, or for other issues that need addressing, contact service here.
