I am running a pro mini using a 12 volt power pack to run to two transformer. One 7.5 volt 3 amp transformer is running the pro mini board. The other 6 volt 3 amp transformer is running a mg 996 servo. The power pack is at 13 volts. The two transformers are putting out the required voltage. All the grounds are tied together. The servo is acting as if the power to it is weak. I am even getting jittery moments in the servo. I have run this set up before with good results. I dont understand why this is happening now. Ant thoughts please? Thank you
Please post a schematic of your project showing how each of the components of it are connected and powered. A 'photo of a hand drawn circuit diagram is good enough
Please post your full sketch, using code tags when you do
I must follow this pheromone trail until I find food. Then I must carry the food back to the nest and the queen will be pleased. 
In my experience, when one says transformer in the context of electronics, that usually implies AC voltage.
Which in the case of both a Pro Mini and a servo, would be really bad.
My thoughts are you need to make a much clearer explanation.
sorry both transformer are DC voltage . I am going to try and send the diagram. Meanwhile I separated the servo from the board using two separate power sources. Same thing erratic. All grounds are common.
That diagram tells me absolutely nothing useful at all. And a DC transformer? I don't know what you're talking about. If you won't be clear, so be it. Good luck.
I don't see a clear, straight connection between the servo negative (ground) and the pro mini. Try connecting them with a wire instead of the round about path shown in the drawing.
All he ground wires are connected together. Now what I just tried was to run the servo and the board on separate power supplies but connecting all the grounds together. I still have the erratic servo function.
Where?
Perhaps "cascaded" (a chain) seems adequate for grounds, but shared-ground-topology should be "star" (central point).
Please post an easily legible wiring diagram.
The thumbnail images are not helpful to us, or to you.
Much better!
It is possible that there is no common ground between the Pro mini and the rest of the system. Check continuity between Gnd and Out- on the right hand converter.