TV Antenna PreAmp 1

If the green LED on the CM-7779HD amplifier is not illuminated, the amplifier is not receiving the required power. If the LED on the power supply is off or flashing, this typically indicates a short or another problem in the coaxial network between the power supply and amplifier.

Use the following steps to troubleshoot the installation.

1. Use good quality RG-6 coaxial cable and connectors

RG-6 coaxial cable is recommended for the PreAmp 1 installation. RG-59 and other types of coaxial cable can have higher resistance, which can reduce the voltage reaching the CM-7779HD amplifier.

If the voltage reaching the amplifier is below its operating requirements, the amplifier may not operate correctly or may operate intermittently. Operating the amplifier with inadequate power for an extended period can also reduce its service life.

2. Inspect all coaxial connectors for shorts

A single improperly installed coaxial connector can prevent the PreAmp 1 from receiving power.

One of the most common problems occurs when a strand of the coaxial cable's metallic braid or shielding touches the copper center conductor. This creates an electrical short between the center conductor and shield.

If the green LED on the power supply is off or flashing, carefully inspect every coaxial cable and connector between the power supply and amplifier.

3. Make sure any splitter between the power inserter and amplifier is power passing

The CM-7779HD receives DC power through the same coaxial cable used to carry the TV signals. Any splitter installed in the coaxial path between the power inserter and amplifier must allow DC power to pass through the appropriate ports.

A standard non-power-passing splitter can block the DC voltage and prevent the CM-7779HD from operating.

Power passing splitters generally look similar to standard splitters, so check the labeling on the splitter rather than assuming it passes power.

4. Remove satellite equipment from the coaxial path

Satellite switches, satellite receivers, and other satellite system components should not be installed in the coaxial path between the PreAmp 1 power inserter and amplifier.

These devices may block the DC voltage required by the CM-7779HD or introduce additional voltage into the coaxial network, which can prevent the amplifier from operating correctly.

5. Make sure the antenna does not have its own built-in amplifier

The PreAmp 1 should not be installed in a configuration that prevents another amplified antenna from receiving the power it requires.

Some amplified antennas include an external device that may appear to be the amplifier. In many cases, this device is actually a power inserter, while the amplifier itself is built into the antenna.

Removing the antenna's original power inserter and replacing it with the PreAmp 1 system may prevent the antenna's internal amplifier from receiving power.

How to test the PreAmp 1 independently

If the CM-7779HD is not receiving power and the cause is not obvious, temporarily remove the amplifier from the antenna installation and test the system independently. This helps determine whether the problem is with the PreAmp 1 components or somewhere in the home's coaxial network.

1. Remove the CM-7779HD amplifier from the mast and bring it inside.
2. Place the amplifier, power inserter, and power supply on a workbench or table.
3. Connect the amplifier to the power inserter using a known-good RG-6 coaxial cable that is 3 feet or shorter.
4. Connect the power inserter to the included power supply.
5. Plug the power supply into AC power.
6. Check the green LEDs on both the power supply and CM-7779HD amplifier.

If both LEDs are steadily illuminated, the amplifier and power components are receiving power and are likely operating normally.

Reinstall the CM-7779HD near the antenna and reconnect it to the home's coaxial network. Check both LEDs again.

If either LED turns off or begins flashing after reconnecting the home's coaxial network, inspect the installation for a damaged coaxial cable, improperly installed connector, center conductor short, non-power-passing splitter, or another device that may be blocking or interfering with DC power.

It is uncommon for the CM-7779HD amplifier to fail while both green LEDs remain steadily illuminated. If both LEDs are on, the amplifier is typically receiving the power required for normal operation.