Hi John,
OK I have just tried both of those and nothing appears, I even deleted the repeater and sub rows and then readded them under a different name, here is my code:
<?php if( have_rows('social') ): ?>
<?php while( have_rows('social') ): the_row(); ?>
<a href="<?php the_sub_field( "media_image" ); ?>" target="_blank"><img src="<?php the_sub_field( "media_link" ); ?>" /></a>
<?php endwhile; ?>
<?php endif; ?>
I don’t see anything wrong there?