What we're saying is that this one was already modified by the builder with the circled brush grounded.
Shouldnt have to change anything
View attachment 1715899847 Check the field as follows: Take a continuity tester (powered light, or an ohm meter). Place one lead on the field terminal and the other on the housing. It should light up, or measure between 2 and 4 ohms.
Then remove the circled brush. Retest the same way. It should not light up , or resistance will show as maximum or infinate.
The alternator pictured below was at some pointed hacked to make it an isolated field alternator.*
View attachment 1715899848
Who knows what it is now.
Test the rotor connections the same way as above.
*See the
Identifying Chrysler Alternator thread for more info about how rebuilders hack alternators.