TRS-80 Color Computer Diagnostics

Cover for a Diagnostics book for the TRS-80 made by Radio Shack.

From the introduction: 
The Diagnostic program for the Color Computer is designed to perform a thorough test of the computer hardware. Hopefully, you will be entertained, as well. The program consists of 11 separate test routines. Each routine evaluates a specific portion of the hardware.

If a problem is indicated when running through one of these tests, we suggest that you go to a Radio Shack store or dealer for the necessary repairs, in order not to void the Warranty. A Radio Shack dealer will also be able to supply you with information regarding BASIC and Expansion ROM CRC values. (See the following “BASIC ROM Test” and “Expansion ROM Test” instructions.)

See the whole book here: https://archive.org/details/ETC2048/page/n3/mode/2up