I have found another way to reset the keyless works in a 7750 without dial/hand removal. This just occured to me as I was re-reading this thread to refresh my memory since I messed up another one last night...
Make sure movement is in winding mode. Insert stem and place movement into winding mode, then remove the stem... movement will not run, and other functions will not work, this is OK
Place movement back into the case (as a holder). Now remove the balance bridge and wheel: remove one screw and carefully remove bridge with tweezers, lifting out the wheel on the spring.
Now use a small pin to gently press the stop lever (#6 in pic balow) all the way back in. Then stick a pin into the stem hole and wiggle it out gently to be sure the castle wheel & gears are free.
Very carefully re-install the balance wheel/bridge and the watch will now run.
Now re-install the crown/stem as per usual, and if all goes well, you've fixed it... without touching the dial side