I am getting the diagnostic error code E23XX (E2311+ E2321+ E2331+ E2341) on my CSA803 or 11800-series oscilloscope. What does this mean?

I am getting the diagnostic error code E23XX (E2311+ E2321+ E2331+ E2341) on my CSA803 or 11800-series oscilloscope. What does this mean?

This diagnostic error code indicates that one or more Row Receptors (E2311, E2331), or Column Receptors (E2321, E2341) do the sense the corresponding emitter. These emitters and receptors provide the touch screen feature of these products.

This problem may be resolved by cleaning the display including the sides where the sensors and emitters are located. Please refer to the service manual for cleaning instructions.

Due to the age of these products, replacement parts are no longer available. Repairs on these products are available from Tektronix Service on a best effort basis.