E-Series OSMAC: Power Distribution Board LEDs

171 March 2, 2022

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

⚠ 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 E-Series OSMAC 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 5V, 9V, and 14V. 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 on the far right-hand side of the Power Distribution Board. The 4-pin power connector will be located directly below the connector for the 20-Pin Decoder Cable. The 4-pin power connector will contain one red wire and one white wire. The red and white 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.

*Note: It is normal for the reading displayed on your digital multimeter or voltmeter to be slightly higher than 12VAC.

If your digital multimeter or voltmeter is displaying a reading lower than 12VAC, the Power Supply Assembly should be tested.

Instructions for testing a Power Supply Assembly can be found 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 disconnect 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 disconnected 8-Station Output Board 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 Receiver/Decoder Module. 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 the 20-Pin Decoder Cable, 4-pin power connector, and all Output/Pump Cables from the Power Distribution Board. 

Using your fingers, pinch the two clips holding the Power Distribution Board in place to release it 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 Receiver/Decoder Module at the known-working satellite location, the Power Distribution Board is damaged and should be replaced.

14V LED:

The 14V LED on the Power Distribution Board indicates the presence of the 14V source that is required for the Receiver/Decoder Module to function properly. If the 14V LED is not illuminated, it is possible that the Receiver/Decoder Module or the Power Distribution Board is damaged. To troubleshoot the absence of the 14V 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 the 20-Pin Decoder Cable from the Receiver/Decoder Module. The Receiver/Decoder module is located at the top of the satellite under the top lid enclosure.

Power the satellite back on.

If the 14V LED on the Power Distribution Board is illuminated after the Receiver/Decoder Module has been disconnected, the Receiver/Decoder Module is damaged and should be replaced.

Replacement Receiver/Decoder Modules can be purchased here.

If the 14V LED is not illuminated after the Receiver/Decoder Module has been disconnected, the Power Distribution Board is damaged and should be replaced.

Replacement Power Distribution Boards should be purchased here.

Lesson tags: toro, e osmac, eosmac, e series osmac, distribution board, LED, 5V, 9V, 12V, repair, replacement, exchange, boardtronics

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