make sure the fields have stored=true
<field name="field_name" type="text_general" indexed="true" stored="true"/>
True if the value of the field should be retrievable during a search.
Use the Default Search Field : The is used by Solr when parsing queries to identify which field name should be searched in queries where an explicit field name has not been used.
<defaultSearchField>collector</defaultSearchField>
in your schema.xml