How do I test baseboard power on my TFT electronic monitor?
If your TFT monitor has power but no response from any of the axis boards—or no visible power light—this guide shows how to test the monitor's baseboard power distribution using a multimeter. It’s a key step before replacing boards or contacting support.
When a monitor isn’t functioning but power is confirmed at the input, the issue could be with the baseboard’s ability to distribute voltage. This test helps determine whether the fault lies in the baseboard or further downstream in the system.
Tools Required
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Multimeter
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Small screwdriver
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Clean work surface
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(Optional) Static protection for components
Step-by-Step Power Testing Procedure
1. Power Down the Monitor
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Always start with the monitor completely powered off.
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Confirm the green indicator light is not illuminated.
2. Remove the Cover
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Unscrew and lift the cover off carefully.
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The cover is attached via a ribbon cable to the communication board.
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To disconnect the ribbon cable:
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Pull up gently on the two side wings to release it.
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Lay the cover aside.
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3. Measure Input Voltage
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Locate the main power supply plug:
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It’s identified by two 14-gauge red and black wires.
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Use your multimeter to measure voltage from the back side of the connector.
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Record this voltage—it will be used for comparison.
4. Remove the Motor and Com Boards
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Unplug the power plug from the baseboard.
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Gently remove all three motor boards and the communication board.
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They are tension-fit and can be removed without disconnecting their wires—just let them hang freely.
5. Reconnect Power and Begin Testing
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Plug the power connector back into the baseboard.
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Use your multimeter:
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Ground one probe.
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Use the other to test power at each board slot.
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Voltage Checks:
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Motor boards: Check the top three pins on the right side of each motor slot—they should match the recorded input voltage.
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Communication board: Test the lower left pin—it should also match the input voltage.
6. Interpret Results
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If all voltages match input: The baseboard is distributing power correctly.
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If one or more slots show no power: The baseboard may be faulty and should be replaced.
7. Reassemble the Monitor
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Power off the system again before reinstalling boards.
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Re-seat each board into its original slot:
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Each set of wires should correspond with its board’s location.
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Ensure boards are fully seated.
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Neatly tuck wires out of the way.
8. Reconnect Ribbon Cable & Lid
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Reconnect the ribbon cable:
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Tan side facing right
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Push it fully into the slot and press the wings back down to lock.
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Lay the ribbon flat over the boards.
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Replace the lid and tighten screws evenly.
What to Do If the Test Fails
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If any slots do not show power, the baseboard may need to be replaced.
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If all voltages are normal but issues persist, contact TFT Tech Support for additional diagnostic procedures.