Why don’t I have 120VAC coming into the satellite?

LESSON SUMMARY: This lesson is designed to assist the user in troubleshooting why there is no 120VAC coming into the satellite.

Special Tools Needed: Digital Multimeter

CAUTION: THIS LESSON MAY INCLUDE INSTRUCTIONS TO TEST HAZARDOUS VOLTAGES (120V-240V) THAT CAN CAUSE SERIOUS INJURY OR DEATH. IT IS RECOMMENDED THAT A LICENSED ELECTRICIAN BE CONTRACTED TO PERFORM SUCH TESTS.

🛑 STOP: ALWAYS TURN OFF THE POWER TO THE SATELLITE BEFORE REMOVING ELECTRONIC COMPONENTS.


If a reliable reading of 120VAC cannot be measured at the utility voltage input for a satellite, it is common for there to be an in-ground wiring issue, particularly if other satellites supplied by the same power feed are operational.

To check for 120VAC at the satellite, proceed with the following steps:

Start by locating the Power Supply Assembly in your satellite. The Power Supply Assembly will typically be located at the base of the satellite inside the satellite enclosure.

Next, power off the satellite using the On/Off switch on the Power Supply Assembly

Remove the Power Supply Assembly from its position in the satellite enclosure to allow access to the rear of unit.

Locate the white 6-position connector containing the utility power wires.

Using a digital multimeter on the AC Voltage setting, place one probe of the multimeter on the incoming HOT/LOAD (black) wire and place the other probe of the multimeter on the incoming NEUTRAL (white) wire. 

*Note: Do not measure the voltage reading between HOT/LOAD and Earth Ground or NEUTRAL and Earth Ground; this is an incorrect method of measuring utility voltage.

This image has an empty alt attribute; its file name is IMG_2816-800x533.jpg
Multimeter probes placed on the pins containing the HOT/LOAD (black) wire and NEUTRAL (white) wire.

When measuring the voltage between HOT/LOAD and NEUTRAL, the multimeter should display a reading at or near 120VAC; a range of 105-130VAC is acceptable.

*Note: When a poor connection in the utility power feed to the satellite is present, oftentimes the voltage reading while the satellite is powered off will be at or near the acceptable range but will drop to zero when the satellite is powered on.

If the voltage reading displayed on the multimeter when measuring between the HOT/LOAD and NEUTRAL wires is not within the acceptable range, proceed to measure the voltage at the nearest point in the power path to the satellite and verify that the voltage reading is within the range of 105-130VAC.

If a voltage reading of 105-130VAC is achieved when measuring at the nearest point in the power path, an inspection of underground wire splices between the satellite location and the point of measurement on the power path is recommended. It is not uncommon for corrosion or lightning to damage connectors or wire splices on the HOT/LOAD and NEUTRAL wires.


Lesson tags: hunter, toro, rain bird, rainbird, buckner, transformer, transformer testing, multimeter, transformer repair, transformer exchange, transformer replacement, 120VAC, boardtronics

©2022 BoardTronics, Inc. All Rights Reserved. (Read Copyright Statement Here)