1979 Seville trip computers

We own two 1979 sevilles with trip computers that don't work. The cars were stored, the guy we rented from needed to move them, the batteries were low, so he jumped them! Zap--now they don't work. If I wiggle the plug that goes into the computer they will "sometimes" work for awhile but not long. Since it/they control the digital dash, it is difficult to drive them. They are both beautiful cars. One an Elegante with factory chrome wires, the other black with deep red interior and chrome wires. We would love to be able to drive them again but can't find anyone to repair our trip computers or find new or used ones. We have had these cars since 1981
Any assistance would be greatly appreciated!

Mitch pat-mitch@insightbb. Com