TM 9-4120-389-14TABLE 4-1. UNIT QUARTERLY PREVENTIVE MAINTENANCECHECKS AND SERVICES (PMCS) - (cont.)ItemItem To BeNo.Inspected/ServicesProcedures9Ventilationa.Remove filter from casing.Filterb.Inspect filter for damage or contaminants.c.Replace damaged filter.d.Clean dirt filter per para. 4-23.4-26