At firealarm.com, we often encounter issues with the Simplex 8562-894 (Audio Control BD 4100). Firstly, ensure all connections are secure and that power is reaching the unit. Check for any visible signs of damage or loose components. If the issue persists, try resetting the device by powering it off for a few minutes and then turning it back on. If these steps don’t resolve the problem, it might be necessary to consult the manufacturer’s manual or contact technical support for further assistance.