MG Car Repair: Midget RVI 1433/01 tachometer, moss motors, black leads

Question
I goofed. I put the battery in as a positive ground in my "69 Midget and started it. Now the tach doesn't work. Might you know what componant has failed or have access to a tach wiring diagram so that I can fix my problem. I thank you very much. Jim/

Answer
Hi Jim,
Do you mean you put it in as a positive ground then changed it back to negative ground and the tach now does not work? I don't have nor have I run across a diagram of the tach itself. We often changed the polarity of MGs with positive ground to negative ground by reversing the red and black leads inside the tach but I never connected a negative ground car up with the positive grounded so I don't know what damage it could do. You should first check to see that the power wire has power on it with the key on and confirm that the ground is making contact. You know the white wires are connected or it would not start. If it is powered and grounded then it may have blown a diode or transistor. Nisinger use to repair tachs but I think Moss Motors does now. You should contact Moss, if they don't, they should know who does now.
Howard