fix: Updated forms and fixed an error.
diff --git a/erpnext/maintenance/doctype/maintenance_schedule/maintenance_schedule.json b/erpnext/maintenance/doctype/maintenance_schedule/maintenance_schedule.json
index 1871228..4df0c6c 100644
--- a/erpnext/maintenance/doctype/maintenance_schedule/maintenance_schedule.json
+++ b/erpnext/maintenance/doctype/maintenance_schedule/maintenance_schedule.json
@@ -229,8 +229,13 @@
  "icon": "fa fa-calendar",
  "idx": 1,
  "is_submittable": 1,
- "links": [],
- "modified": "2021-04-16 15:53:36.670816",
+ "links": [
+  {
+   "link_doctype": "Maintenance Visit Purpose",
+   "link_fieldname": "prevdoc_docname"
+  }
+ ],
+ "modified": "2021-04-21 11:27:05.744109",
  "modified_by": "Administrator",
  "module": "Maintenance",
  "name": "Maintenance Schedule",
diff --git a/erpnext/maintenance/doctype/maintenance_schedule_detail/maintenance_schedule_detail.json b/erpnext/maintenance/doctype/maintenance_schedule_detail/maintenance_schedule_detail.json
index f1e2e21..76acefb 100644
--- a/erpnext/maintenance/doctype/maintenance_schedule_detail/maintenance_schedule_detail.json
+++ b/erpnext/maintenance/doctype/maintenance_schedule_detail/maintenance_schedule_detail.json
@@ -9,10 +9,14 @@
  "field_order": [
   "item_code",
   "item_name",
+  "column_break_3",
   "scheduled_date",
-  "sales_person",
   "actual_date",
+  "section_break_6",
+  "sales_person",
+  "column_break_8",
   "completion_status",
+  "section_break_10",
   "serial_no",
   "item_ref"
  ],
@@ -95,15 +99,33 @@
   },
   {
    "fieldname": "item_ref",
-   "fieldtype": "Data",
+   "fieldtype": "Link",
+   "hidden": 1,
    "label": "Item Reference",
+   "options": "Maintenance Schedule Item",
    "read_only": 1
+  },
+  {
+   "fieldname": "column_break_3",
+   "fieldtype": "Column Break"
+  },
+  {
+   "fieldname": "section_break_6",
+   "fieldtype": "Section Break"
+  },
+  {
+   "fieldname": "column_break_8",
+   "fieldtype": "Column Break"
+  },
+  {
+   "fieldname": "section_break_10",
+   "fieldtype": "Section Break"
   }
  ],
  "idx": 1,
  "istable": 1,
  "links": [],
- "modified": "2021-04-19 17:42:31.685710",
+ "modified": "2021-04-21 11:07:29.524071",
  "modified_by": "Administrator",
  "module": "Maintenance",
  "name": "Maintenance Schedule Detail",
diff --git a/erpnext/maintenance/doctype/maintenance_visit/maintenance_visit.js b/erpnext/maintenance/doctype/maintenance_visit/maintenance_visit.js
index d5e8e51..403d1ab 100644
--- a/erpnext/maintenance/doctype/maintenance_visit/maintenance_visit.js
+++ b/erpnext/maintenance/doctype/maintenance_visit/maintenance_visit.js
@@ -34,16 +34,21 @@
 	},
 	onload: function (frm, cdt, cdn) {
 		let item = locals[cdt][cdn];
-		let s_id = item.purposes[0].prevdoc_detail_docname;
-		frappe.call({
-			method: "erpnext.maintenance.doctype.maintenance_schedule.maintenance_schedule.update_serial_nos",
-			args: {
-				s_id: s_id
-			},
-			callback: function (r) {
-				serial_nos = r.message;
-			}
-		});
+		if (frm.maintenance_type == 'Scheduled') {
+
+			let s_id = item.purposes[0].prevdoc_detail_docname;
+			frappe.call({
+				method: "erpnext.maintenance.doctype.maintenance_schedule.maintenance_schedule.update_serial_nos",
+				args: {
+					s_id: s_id
+				},
+				callback: function (r) {
+					serial_nos = r.message;
+				}
+			});
+
+		}
+
 		if (!frm.doc.status) {
 			frm.set_value({ status: 'Draft' });
 		}
diff --git a/erpnext/maintenance/doctype/maintenance_visit_purpose/maintenance_visit_purpose.json b/erpnext/maintenance/doctype/maintenance_visit_purpose/maintenance_visit_purpose.json
index 60e5afe..0d19d70 100644
--- a/erpnext/maintenance/doctype/maintenance_visit_purpose/maintenance_visit_purpose.json
+++ b/erpnext/maintenance/doctype/maintenance_visit_purpose/maintenance_visit_purpose.json
@@ -9,10 +9,12 @@
  "field_order": [
   "item_code",
   "item_name",
+  "column_break_3",
+  "service_person",
   "serial_no",
+  "section_break_6",
   "description",
   "work_details",
-  "service_person",
   "work_done",
   "prevdoc_doctype",
   "prevdoc_docname",
@@ -86,6 +88,7 @@
   {
    "fieldname": "prevdoc_doctype",
    "fieldtype": "Link",
+   "hidden": 1,
    "label": "Document Type",
    "no_copy": 1,
    "oldfieldname": "prevdoc_doctype",
@@ -114,6 +117,7 @@
   {
    "fieldname": "prevdoc_detail_docname",
    "fieldtype": "Link",
+   "hidden": 1,
    "label": "Against Document Detail No",
    "no_copy": 1,
    "oldfieldname": "prevdoc_detail_docname",
@@ -124,12 +128,20 @@
    "read_only": 1,
    "report_hide": 1,
    "width": "160px"
+  },
+  {
+   "fieldname": "column_break_3",
+   "fieldtype": "Column Break"
+  },
+  {
+   "fieldname": "section_break_6",
+   "fieldtype": "Section Break"
   }
  ],
  "idx": 1,
  "istable": 1,
  "links": [],
- "modified": "2021-04-19 16:08:10.671163",
+ "modified": "2021-04-21 11:16:52.025914",
  "modified_by": "Administrator",
  "module": "Maintenance",
  "name": "Maintenance Visit Purpose",