Note 1: Cable TV systems can contribute to ground loop problems, which in turn, cause “hum.” To determine whether your cable system is the contributing factor, disconnect the cable TV incoming signal line (the round, 75 ohm cable) before it first connects to your system. If the hum disappears, you should insert a “75 ohm Ground Loop Isolator” between the cable down lead and your system. Check with your ADCOM Dealer to obtain one. If the isolator does not fully cancel the hum, please read Note 2 to complete the troubleshooting procedure.
Note 2: Make sure that the power amplifier is at least 6" from the Tuner/Pre-amp. Usually, putting another compo- nent between these two units is sufficient to minimize the hum. If this does not work, turn the system off and disconnect all input cables from the amplifier. Turn the system on again. If the hum persists, your Dealer or Service Center should check the amplifier. If the hum disappears, try another set of RCA cables. (Remember to turn your entire system off whenever you change cables. You may also need to wait a few moments after turning the amplifier off until the power supply discharges to avoid nasty “thumps” when you disconnect or con- nect cables.) Connect one RCA cable at a time to see if the hum returns and, if it does, which specific cable is responsible. Replace that cable. If the hum persists with any (or all) cables, then your GTP-760 should be checked by your Dealer or Authorized Service Center.
