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MODEL-SPECIFIC DIAGNOSTIC

Diagnostics / SMART / MX series

SMART Board MX shows the computer but touch does not control it

The external computer picture is visible, while touch remains unavailable on that source.

Applies to this documented familySBID-MX265, SBID-MX275, SBID-MX286

Likely causes, most useful checks first

  • The touch USB path is not connected.
  • The touch connection is paired with another video input.
  • An extender or dock interrupts USB.
  • The computer has not enumerated the touch device.

Safe checks

01

Test touch outside the computer input

Open the display's own interface and test touch there.

What the result means: Working display-local touch narrows the issue to the external USB path.

02

Check the paired USB connection

Follow the exact MX model's connection diagram and confirm the USB touch cable matches the active video input.

What the result means: Correct the external pairing and retest.

03

Bypass the room signal chain

Connect the computer directly with known-good video and USB cables.

What the result means: If direct works, inspect the external wall plate, extender or dock.

Sources

Reviewed under the BoardFaults safe-external-check policy · risk class: low · updated 2026-09-03