Network LTC Plus: Power Distribution Board LEDs

LESSON SUMMARY: This lesson is designed to assist the user in understanding what each LED on the Power Distribution Board represents and what an absence of any one, or multiple, LEDs being illuminated could mean.

Special Tools Needed: Digital Multimeter, Phillips Screwdriver

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 OR INSTALLING COMPONENTS.


The SuperParts™ Power Distribution Board for Network LTC® Plus is equipped with three LEDs that indicate the presence of voltages needed for components in the satellite to function properly. The three LEDs indicate the presence of 24VAC, 5V, and 9V. The Conversion Distribution Board for Network LTC® Plus to Network VP® upgrade has four LEDs: 24VAC, 5V, 9V, and 12V. To determine the cause of any one, multiple, or all LEDs on the Power Distribution Board not illuminating, follow the guided steps below.


No LEDs Illuminated:

If the Power Distribution Board has no voltage LEDs illuminated, the incoming voltage from the Power Supply Assembly to the Power Distribution Board will need to be measured. 

*Note: The following steps should be completed without powering off the satellite.

Start by locating the 4-pin power connector in the center of the Power Distribution Board. There will be two 4-pin power connectors directly next to each other. You will need to measure voltage from the 4-pin power connector located on the right. The 4-pin power connector will contain one red wire, one white, one black wire and one green wire. The red, white, black and green wires supply power from the Power Supply Assembly to the Power Distribution Board.

Using a digital multimeter or voltmeter on the AC Voltage setting, place one probe of the multimeter or voltmeter on the pin containing the red wire and one probe on the pin containing the white wire.

Proper reading of ~12VAC

Your digital multimeter or voltmeter should display a reading of 12VAC; up to 16VAC is acceptable.

After measuring the voltage for the red and white wires, proceed to measure the voltage for the black and green wires.

Using a digital multimeter or voltmeter on the AC Voltage setting, place one probe of the multimeter or voltmeter on the pin containing the black wire and one probe on the pin containing the green wire.

Your digital multimeter or voltmeter should display a reading of 24VAC; up to 30VAC is acceptable.

If your digital multimeter or voltmeter is displaying a reading lower than 12VAC when measuring the voltage for the red and white wires, or less than 24VAC when measuring the voltage for the black and green wires , the Power Supply Assembly should be tested.


24VAC LED:

The 24VAC LED on the Power Distribution Board indicates the Power Supply Assembly is providing adequate 24VAC to the Power Distribution Board. Without 24VAC present, the satellite will not be able to run stations. If the 24VAC LED is not illuminated, the Power Supply Assembly should be checked using the troubleshooting guide here.


5V LED:

The 5V LED on the Power Distribution Board indicates the presence of the 5V source that is required for the drivers on the 8-Station Output Boards to function properly. If the 5V LED is not illuminated, it is possible that the Power Distribution Board or one or more of the 8-Station Output Boards is damaged. To troubleshoot the absence of the 5V LED being illuminated, proceed with the following steps:

Start by powering off the satellite using the On/Off rocker switch located on the front of the Power Supply Assembly. 

Next, unplug only the Output/Pump Cable from the Power Distribution Board for the highest-numbered 8-Station Output Board in the satellite. Example: If your satellite is configured to run 32 stations, you would unplug the Output/Pump Cable for the 8-Station Output Board located in the fourth position of the Power Distribution Board. The 8-Station Output Board in the fourth position will run stations 24-32 and will be located in the furthest position on the right-hand side of the satellite.

Power the satellite back on. 

If the 5V LED on the Power Distribution Board is illuminated, the 8-Station Output Board in the fourth position is damaged and should be replaced. 

If the 5V LED on the Power Distribution Board  is not illuminated, repeat the preceding steps for the remaining 8-Station Output Boards installed in the satellite. It is recommended that the 8-Station Output Boards be tested in descending order. Example: If your satellite is configured to run 32 stations, and you have tested the 8-Station Output Board located in the fourth position of the Power Distribution Board, you will proceed to test the 8-Station Output Board located in the third position of the Power Distribution Board. The 8-Station Output Board in the third position will run stations 16-24.

*Note: The satellite should be powered off between testing each individual 8-Station Output Board. 

If all 8-Station Output Boards installed in the satellite have been tested and are known to be working properly, the Power Distribution Board is damaged and should be replaced.


9V LED:

The 9V LED on the Power Distribution Board indicates the presence of the 9V source that is required for the relays on the 8-Station Output Boards to function properly. If the 9V LED is not illuminated you will not be able to run stations from the Timing Mechanism. If the 9V LED is not illuminated it is likely that the Power Distribution Board is damaged. To troubleshoot the absence of the 9V LED being illuminated, proceed with the following steps:

Start by powering off the satellite using the On/Off rocker switch located on the front of the Power Supply Assembly. 

Next, unplug all cables and connectors from the Power Distribution Board, including the Data Cable, 3-pin Power Cable, 4-pin Power Cable(s), and all Output/Pump Cables.

Using a Phillips screwdriver, unscrew the mounting screws used to hold the 8-Station Output Boards in place. Remove all 8-Station Output Boards from the satellite to access the Power Distribution Board.

Using a Phillips screwdriver, unscrew the mounting screws used to hold the Pump Common in place. Remove the Pump Common from the satellite to access the Power Distribution Board.

Using a Phillips screwdriver, unscrew the mounting screws used to hold the Power Distribution Board in place. Remove the Power Distribution Board from the satellite.

Take the Power Distribution Board to a known-working satellite location to test.

*Note: Prior to installing the Power Distribution Board at a known-working satellite location, be sure to power off the satellite at the known-working satellite location. Power to the satellite should always be off before installing or removing components.

If the 9V LED is not illuminated when the Power Distribution Board is installed in a known-working satellite location, and you are unable to run stations from the Timing Mechanism at the known-working satellite location, the Power Distribution Board is damaged and should be replaced.


12V LED:

The 12V LED is only present on the SuperParts™ Conversion Distribution Board for Network LTC® Plus to Network VP® upgrade. The 12V LED on the Power Distribution Board indicates the presence of the 12V source that is required for the Timing Mechanism and Modem (if installed) to function properly. If the 12V LED is not illuminated, it is possible that the Timing Mechanism, Modem or the Power Distribution Board is damaged. It is also possible that there is no voltage being supplied by the 12V source. To troubleshoot the absence of the 12V LED being illuminated, proceed with the following steps:

*Note: If a Modem is installed in the satellite and 12V is not present, central communication will not work.

Start by powering off the satellite using the On/Off rocker switch located on the front of the Power Supply Assembly.  

Next, unplug the Modem Cable from the Timing Mechanism. The Modem Cable connects the Modem to the Timing Mechanism.

Power the satellite back on.

If the 12V LED on the Power Distribution Board is illuminated after the Modem has been disconnected from the Timing Mechanism, the Modem is damaged and should be replaced.

If the 12V LED is not illuminated after the Modem has been disconnected from the Timing Mechanism, proceed to test the Timing Mechanism.

Replacement Standard Modems can be purchased here.

To test the Timing Mechanism, start by powering the satellite off and unplug the 40-Pin Cable from the base of the Timing Mechanism.

Power the satellite back on.

If the 12V LED on the Power Distribution Board is illuminated after the 40-Pin Cable has been disconnected from the Timing Mechanism, the Timing Mechanism is damaged and should be replaced.

Replacement Timing Mechanisms can be purchased here.

If the 12V LED is not illuminated after the 40-Pin Cable has been disconnected from the Timing Mechanism, the Power Distribution Board is damaged and should be replaced.

Replacement Power Distribution Boards can be purchased here.


Lesson tags: toro, network ltc plus, distribution board, LED, 24VAC, 5V, 9V, 12V, repair, replacement, exchange, boardtronics

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