I wound up replacing the ribbon cable and connector ends where it connects to the ATC and where it connects to the LCD card. All of the parts I used came from Digi-Key. Header connector at display is CWR-220-14-0000 [DigiKey stock # CSC14G-ND], the D-Sub15 connector at the ATC is A-DSF-15PIII-Z [DigiKey stock # HHMM15H-ND] and the ribbon cable spool is 302-28-14-GR-0100F [DigiKey stock # CN218GR-100-ND]. This solved the issue of a worn ribbon cable and loose connections - be sure to note cable stripe/connector orientations, and make sure connectors are seated tightly/squarely on ribbon. $34 for the parts plus shipping. Cheaper than $1,100 I had quoted for a new card assembly. Thanks for the input from John in Europe on disconnecting main power to reset the relays in the ATC. Everything is working again! I hope this info can help somebody else!