User manual AKG K 406 AFC

[. . . ] Using the transmitter with a different AC adapter voids the warranty. Always switch the headphones OFF after use. Never place the equipment near heat sources such as radiators or electric heaters or expose it to direct sunlight, excessive dust, humidity, rain, temperatures below freezing, or impacts. Never use alcohol, petroleum-based cleaners, or paint thinners to clean the headphones or transmitter. [. . . ] 3 Charging the Batteries in the Headphones In order to ensure the longest possible service life for the rechargeable batteries, we deliver them uncharged, inside the headphones. Therefore, you will need to charge the supplied batteries before first operating your headphones system. Before charging, pull the protective foil away from the earphone in a straight movement. WARNING: If you operate the headphones on dry batteries (see section 6. 4), never try to charge the batteries using the transmitter's charging feature. This would cause serious damage to your headphone system. Important: In order to maintain full battery capacity for as long as possible, discharge the batteries completely about once a month: Switch the headphones on and leave them outside the transmitter until the status LED (2) extinguishes. 1 Optional External Charger Alternatively, you use can the optional external charger to charge the batteries as shown in fig. Plug the charger into a convenient power outlet. the status LED (2) on the headphones will illuminate red to indicate that the batteries are being charged. Note: You can use the K 306 AFC and K 406 AFC headphones even while charging batteries. If you feel that you need to recharge the supplied batteries more often than would be convenient, you may consider replacing the batteries with new AAA size 1. Remove the ear pad from the left-hand earphone as shown in fig. 10, insert the new batteries into the battery compartment (4). Make sure to align the batteries with the polarity marks inside the battery compartment. Replace the ear pad on the earphone and rotate the ear pad CW to the point that the ear pad will click into place. If audio signal is present at the transmitter input, the POWER ON/CHARGE LED (11) on the transmitter will light green. After a few seconds, you should hear the signal in the headphones clearly and free of interference. [. . . ] Interference caused by other users of the 864 MHz LPD band are beyond AKG's control. Batteries are not correctly aligned with polarity marks. Audio level at transmitter input is too low. Audio level at transmitter input is too high. [. . . ]