TAG Heuer

But does anyone happen to know the movement used in the F1 series 1 from 1986? It’s the watch that first got me into watches as a child, and I tracked one down a mint condition one a couple of years back, but it’s finally given up (tried a battery change)...  

But what a fun watch 😀

from back in the day! Sorry I can't be of help where the movement is concerned.

...  

and do a transplant op?

(you of course used the correct battery and put it in with polarity the right way) - I doubt there is much that can be done to these rather simple Ronda, ESA or ETA movements in terms of repair. The assembly company putting together sourced parts for TAG ...