jp1993 I've had several issues with T-Rex over the years so I know him well. Is his head going all the way down to the saucer? If so, it could be one of two things:
1. Down switch is not activated. If you raise the play field, you'll see a series of switches surrounding T-Rex that let him know where he is positioned. He won't do certain things unless certain switches are activated.
Example: he can only bend down if the center switch is activated. Or, he will only chomp if the down switch is activated.
The other possible item and more likely issue is that the wire that goes from under T-Rex to the chomping coil/solenoid has been damaged from years of moving back and forth. This is quite common and mine was very hard to determine because you have to cut the sheathing that contains multiplied wires. One wire in the bundle was broken and I had to do in in-line solder to get it connected again.
Start with that and you should be able to find the issue.
Regarding the flipper, it sounds like an EOS issue. Search the forum or google and you'll come up with several topics regarding that.