I accidentally plug in a 110V Companion 5 system into a 220V supply I am a technician could you guide me where to locate the fault and what what componenents would be required to be replaced

If you are a circuit designer, I am sure that you know that most electronic equipment has fuses inline with the AC input, and sometimes a circuit breaker, or a fusible resistor. Also, if you are a circuit designer, surely you know that the inductive reactance of a transformer primary could limit the risetime of the input current, depending heavily on the instantaneous phase of the sinusoidal waveform applied to the input, so a slow-blow fuse could fail to interrupt the input current flow before the voltage on the internal power supply was far too high to be safe! Do you have a schematic of the unit that endured the input of an value of double what it was designed for? As a starting point, if I were you, I would wire a 100-150 watt incandescent light in SERIES with the AC input of the suspected defective unit, so that if there is a short or low impedance on the input to that device, the voltage and current available to the device under test will be limited by the light bulb load, and you will see the light glowing. With the unit connected that way, an oscillograph ('scope display) of the input voltage across the AC input of the suspected defective unit can tell you a lot! If you are a circuit designer, I am sure that you know that most electronic equipment has fuses inline with the AC input, and sometimes a circuit breaker, or a fusible resistor. Also, if you are a circuit designer, surely you know that the inductive reactance of a transformer primary could limit the risetime of the input current, depending heavily on the instantaneous phase of the sinusoidal waveform applied to the input, so a slow-blow fuse could fail to interrupt the input current flow before the voltage on the internal power supply was far too high to be safe! Do you have a schematic of the unit that endured the input of an value of double what it was designed for? As a starting point, if I were you, I would wire a 100-150 watt incandescent light in SERIES with the AC input of the suspected defective unit, so that if there is a short or low impedance on the input to that device, the voltage and current available to the device under test will be limited by the light bulb load, and you will see the light glowing. With the unit connected that way, an oscillograph ('scope display) of the input voltage across the AC input of the suspected defective unit can tell you a lot!