[. . . ] Rotel products are designed to comply with international directives on the Restriction of Hazardous Substances (RoHS) in electrical and electronic equipment and the disposal of Waste Electrical and Electronic Equipment (WEEE). The crossed wheelie bin symbol indicates compliance and that the products must be appropriately recycled or processed in accordance with these directives. WARNING: To reduce the risk of fire or electric shock, do not expose the unit to moisture or water. If the unit is exposed to moisture, or a foreign object gets into the enclosure, immediately disconnect the power cord from the wall. [. . . ] Shipping or moving the RKB-250 in anything other than the original packing material may result in severe damage to your amplifier. It is your best record of the date of purchase, which you will need in the event warranty service is ever required. However, when rack mounting or otherwise installing the amplifier in a confined space near other heat-generating components, additional cooling may be desirable. The optional RKBF-1 fan kit can be easily installed for additional forced air cooling. In addition to lowering operating temperatures, the optional fan kit improves the performance of the amplifier, especially when driving difficult loudspeaker loads. When not using an equipment rack, place the RKB-250 on a solid, level surface away from sunlight, heat, moisture, or vibration. When using the fan cooling, select a location for the amplifier where the noise will not be intrusive. Your RKB-250 is configured at the factory for the proper AC line voltage in the country where you purchased it (USA: 120 volts/60 Hz, Europe: 230 volts/50 Hz). Be sure the power switch on the front panel of the RKB-250 is turned off. Then, plug one end of the cord into the AC power connector on the back panel of the amplifier. If you are going to be away from home for an extended period of time, it is a sensible precaution to unplug your amplifier. With the switch in the SIGNAL SENSE position, the amplifier turns on automatically when a signal is detected at the inputs. The amplifier will go into standby mode several minutes after no signal is no longer present. Turning the switch OFF cuts power to the amplifier, regardless of whether or not a signal is present. With the switch in the 12V TRIG position, the amplifier is turned on automatically when a 12 volt trigger signal is present at the 12V TRIG input to the left of the switch. The amplifier goes into standby mode if the +12 volt signal is not present. Turning the switch OFF cuts power to the amplifier, regardless of whether or not a trigger signal is present. Instead, the protection circuit monitors the temperature of the output devices and shuts down the amplifier if temperatures exceed safe limits. In addition, the RKB-250 includes overcurrent protection which operates only when load impedance drops too low. Should a faulty condition arise, the amplifier will stop playing and one or both of the PROTECTION LEDS on the front panel will light indicating a fault with the left and/or right channels. [. . . ] if the polarity of one connection is mistakenly reversed , bass output will be very weak and stereo imaging degraded. The wire may have clear insulation with different color conductors (copper and silver). This pair of RCA connections can be used to pass the unprocessed input signals to another audio component, for example to "daisychain" an additional amplifier to drive a second set of speakers. Connect the left speaker to the pair of speaker connectors labeled LEFT. [. . . ]