I am getting the diagnostic error code E1A11 on my CSA803 or 11800-series oscilloscope. What does this mean?

I am getting the diagnostic error code E1A11 on my CSA803 or 11800-series oscilloscope. What does this mean?

This diagnostic error code indicates a problem with U500, the Numeric Processor Extension. The value returned of a pre-determined equation was not within +0.005 of the expected value.

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.