E-Series OSMAC: (Video) Improper Station Functionality

Video Text Summary

LESSON SUMMARY: This lesson is designed to assist the user in troubleshooting what would cause an 8-Station Output Board to have one, or multiple, of its relays continuously clicking or stuck in “test mode.”

Special Tools Needed: Needle Nose or Long Nose Pliers, 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.


If one or more relays on an E-OSMAC 8-Station Output Board are clicking/stuck in “test mode”, there could be an issue with the Receiver/Decoder Module, Pump Common, Power Distribution Board, or an 8-Station Output Board. Follow the guided steps below to determine which component(s) require replacement.

Receiver/Decoder Module:

The Receiver/Decoder Module is located at the top of the satellite under the top lid enclosure. To test the Receiver/Decoder Module 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, using a pair of needle nose or long nose pliers, pinch the white clips holding the Receiver/Decoder Module in place to release it from it’s bezel. 

Proceed to unplug the 20-Pin Decoder Cable from the Power Distribution Board. 

Take the Receiver/Decoder Module and the 20-Pin Decoder Cable to a known-working satellite location to test.

*Note: Prior to installing Receiver/Decoder Module and 20-Pin Decoder Cable 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.

Once installed in the known-working satellite location, if the relay clicking/stuck in “test mode” issue persists, the Receiver/Decoder Module is damaged and should be replaced.

If the relay clicking/stuck in “test mode” issue is resolved when the Receiver/Decoder Module is installed in a known-working satellite location, further troubleshooting is required in the original satellite location.

Replacement Receiver/Decoder Modules can be purchased here.

*Note: It is possible for corrosion on the 20-Pin Decoder Cable that connects the Receiver/Decoder Module to the Power Distribution Board to cause a relay to click/be stuck in “test mode.” Visually inspect the 20-Pin Decoder Cable for any signs of corrosion damage. Corrosion damage will typically appear in the cable connectors. If any corrosion is found, discard the cable and replace it with a new or known-working 20-Pin Decoder Cable. You may also test the cable by installing it in a known-working satellite location. If the relay clicking/”test mode” issue continues when the 20-Pin Decoder Cable is installed in a known-working satellite location, the cable is damaged and needs to be replaced.

Replacement 20-Pin Decoder Cables can be purchased here.

If the Receiver/Decoder Module and 20-Pin Decoder cable have been tested and found to be working properly, you may reinstall them in the original satellite location. Further troubleshooting at the original satellite location is required.


Pump Common:

The Pump Common is located in the satellite along the far left-hand side. To test the Pump Common 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 Output/Pump Cable from the Power Distribution Board that is connected to the Pump Common. You may leave the Pump Common mounted in the satellite. 

Power the satellite back on.

If the relay clicking/test mode issue is resolved, the Pump Common is damaged and should be replaced.

If the relay clicking/test mode issue persists while the Pump Common is disconnected from Power Distribution Board, further troubleshooting is required.

Replacement Pump Commons can be purchased here.

*Note: It is possible for corrosion on the Output/Pump Cable that connects the Pump Common to the Power Distribution Board to cause a relay to click/be stuck in “test mode.” Visually inspect the Output/Pump Cable for any signs of corrosion damage. Corrosion damage will typically appear in the cable connectors. If any corrosion is found, discard and replace with a new or known-working Output/Pump Cable. You may also test the cable by installing it in a known-working satellite location. If the relay clicking/”test mode” issue continues when the Output/Pump Cable is installed in a known-working satellite location, the cable is damaged and needs to be replaced.

Replacement Output/Pump Cables can be purchased here.

If the Pump Common has been tested and is found to be working properly, you may reconnect the Output/Pump Cable to the Power Distribution Board. Further troubleshooting is required.


Power Distribution Board:

The Power Distribution Board is located at the top of the satellite below the Receiver/Decoder Module and above the 8-Station Output Boards. To test the Power Distribution Board 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 Output/Pump Cables from the Power Distribution Board for all 8-Station Output Boards installed in the satellite. The Output/Pump Cable is the cable that connects the 8-Station Output Boards to the Power Distribution Board.

Using a Phillips screwdriver, unscrew the mounting screws used to hold the 8-Station Output Board that is located in the first position of the Power Distribution Board in place. The 8-Station Output Board in the first position will be located on the left side of the satellite directly next to the Pump Common.

Disconnect the 8-Station Output Board from the 16-Station Switch & Surge Board and remove it from the satellite.

Proceed to install a known-working 8-Station Output Board in the first position of the Power Distribution Board.

*When installing a known-working 8-Station Output Board in the first position of the Power Distribution Board, make sure to reconnect the 8-Station Output Board to the 16-Station Switch & Surge Board and plug the Output Pump Cable back into the Power Distribution Board.

Power the satellite back on.

If the relay clicking/”test mode” issue persists, the Power Distribution Board is damaged and should be replaced.   

If the relay clicking/”test mode” issue is resolved, further troubleshooting is required.

Replacement Power Distribution Boards can be purchased here.


8-Station Output Board:

The 8-Station Output Boards are located in the middle of the satellite and connect to both the Power Distribution Board and the 16-Station Switch & Surge Boards. To test the 8-Station Output Boards, 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 Output/Pump Cables from the Power Distribution Board for all 8-Station Output Boards installed in the satellite, with the exception of the 8-Station Output Board located in the first position of the Power Distribution Board. The 8-Station Output Board in the first position will be located on the left side of the satellite directly next to the Pump Common. 

With the 8-Station Output Board still plugged into the first position of the Power Distribution Board, power the satellite back on.

If the relay clicking/”test mode” issue is not present for the single 8-Station Output Board connected to the Power Distribution Board after powering the satellite back on, the 8-Station Output Board is functioning properly.

If the relay clicking/”test mode” issue is still present for the single 8-Station Output Board connected to the Power Distribution Board after powering the satellite back on, the 8-Station Output Board is damaged and should be replaced.

Proceed to test each 8-Station Output Board in the satellite in the first position of the Power Distribution Board to verify that each 8-Station Output Board is functioning properly.

If during the course of your testing you find that one of your 8-Station Output Boards is the source of the relay clicking/”test mode” issue, you may further verify by testing the 8-Station Output Board in a known-working satellite location.

*Note: Prior to installing the 8-Station Output 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 relay clicking/”test mode” issue persists when the 8-Station Output Board is installed in a known-working satellite location, the 8-Station Output Board is damaged and should be replaced.

Replacement 8-Station Output Boards can be purchased here.


Lesson tags: toro, eosmac, toro eosmac, e series osmac, eosmac repair, eosmac help, eosmac troubleshooting, eosmac exchange, eosmac motherboard, eosmac output board, eosmac receiver decoder, osmac decoder, pump common, power distribution board, output cables, boardtronics

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