As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE ON GND UNABLE TO MANUALLY SELECT EEC SECONDARY CHANNEL FROM SECONDARY SELECT SWITCH AT P61 PANEL. FOUND CONTACT Y1 PUSHED BACK ON CONNECTOR D5860. SECURED CONTACT IN CONNECTOR. SECONDARY CONTROL MESSAGE SHOWS AND SEC CHANNEL SELECTED ON EPCS PAGE WHEN SELECTED ON P61 PANEL.