A new method of developing and presenting troubleshooting information for semi-automatic checkout equipment has been developed for the Mark 6 Re-entry Vehicle program based upon the signal-flow method of analysis. This analysis enables the technician to logically eliminate all sources of malfunction which might produce a given erroneous output. It has been proven to be effective in reducing system down-time and in assisting in training of technicians. This method may be useful for other fixed-sequence checkout operations.