I am getting the diagnostic error code D1XXX (D1111+ D1121+ D1211+ D1221) on my CSA803 or 11800-series oscilloscope. What does this mean?

I am getting the diagnostic error code D1XXX (D1111+ D1121+ D1211+ D1221) on my CSA803 or 11800-series oscilloscope. What does this mean?

D1111 and D1211 indicate problems with ROM, U140. The device is either not in the socket, the socket has failed, or the checksum does not match.

Error codes D1121 and D1221 indicate problems with U150. The device is either not in the socket, the socket has failed, or the checksum does not match.

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.