Wordpress - Order by DESC, ASC in custom WP_Query

Try this:

$args = array(
        'post_type' => 'post',
        'meta_key' => 'pb_issue_featured',
        'orderby'   => 'meta_value',
        'order' => 'DESC',
        'posts_per_page' => $posts,
        'paged' => $paged,
        'paged' => 1,
        'meta_query' => array(
            array(
                'key' => 'headline',
                'value' => 1,
                'compare' => '!=' 
                )
            )
        );

add_filter( 'posts_orderby', 'filter_query' );
$q = new WP_Query($args);
remove_filter( 'posts_orderby', 'filter_query' );

function filter_query( $query ) {
    $query .= ', wp_posts.menu_order ASC';
    return $query;
}