diff --git a/src/pvi/device.py b/src/pvi/device.py
index cb3dfd2c..e7e09d11 100644
--- a/src/pvi/device.py
+++ b/src/pvi/device.py
@@ -308,10 +308,12 @@ class SignalR(Signal):
 
     read_pv: str = Field(description="PV to use for readback")
     read_widget: ReadWidgetUnion = Field(
-        None, description="Widget to use for display. `TextRead` will be used if unset."
+        None,
+        description="Widget to use for display. `TextRead` will be used if unset.",
+        validate_default=True,
     )
 
-    @field_validator("read_widget")
+    @field_validator("read_widget", mode="before")
     @classmethod
     def _validate_read_widget(cls, read_widget: Any):
         if read_widget is None:
diff --git a/tests/format/input/signal_default_widgets.pvi.device.yaml b/tests/format/input/signal_default_widgets.pvi.device.yaml
new file mode 100644
index 00000000..5d6cc223
--- /dev/null
+++ b/tests/format/input/signal_default_widgets.pvi.device.yaml
@@ -0,0 +1,25 @@
+# yaml-language-server: $schema=../../../schemas/pvi.device.schema.json
+
+label: label
+children:
+
+- type: SignalR
+  name: Read
+  read_pv: Read
+
+- type: SignalW
+  name: Write
+  write_pv: Write
+
+- type: SignalRW
+  name: ReadWriteSingle
+  write_pv: ReadWriteSingle
+
+- type: SignalRW
+  name: ReadWrite
+  write_pv: ReadWrite
+  read_pv: ReadWrite_RBV
+
+- type: SignalX
+  name: Execute
+  write_pv: Execute
diff --git a/tests/format/output/signal_default_widgets.bob b/tests/format/output/signal_default_widgets.bob
new file mode 100644
index 00000000..b06b023a
--- /dev/null
+++ b/tests/format/output/signal_default_widgets.bob
@@ -0,0 +1,138 @@
+<display version="2.0.0">
+  <name>Display</name>
+  <x>0</x>
+  <y use_class="true">0</y>
+  <width>274</width>
+  <height>150</height>
+  <grid_step_x>4</grid_step_x>
+  <grid_step_y>4</grid_step_y>
+  <widget type="label" version="2.0.0">
+    <name>Title</name>
+    <class>TITLE</class>
+    <text>label</text>
+    <x use_class="true">0</x>
+    <y use_class="true">0</y>
+    <width>274</width>
+    <height>26</height>
+    <font use_class="true">
+      <font name="Header 1" family="Liberation Sans" style="BOLD" size="22.0">
+      </font>
+    </font>
+    <foreground_color use_class="true">
+      <color name="Text" red="0" green="0" blue="0">
+      </color>
+    </foreground_color>
+    <transparent use_class="true">true</transparent>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="label" version="2.0.0">
+    <name>Label</name>
+    <text>Read</text>
+    <x>22</x>
+    <y>30</y>
+    <width>120</width>
+    <height>20</height>
+  </widget>
+  <widget type="textupdate" version="2.0.0">
+    <name>TextUpdate</name>
+    <pv_name>Read</pv_name>
+    <x>146</x>
+    <y>30</y>
+    <width>124</width>
+    <height>20</height>
+    <font>
+      <font name="Default Bold" family="Liberation Sans" style="BOLD" size="14.0">
+      </font>
+    </font>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="label" version="2.0.0">
+    <name>Label</name>
+    <text>Write</text>
+    <x>22</x>
+    <y>54</y>
+    <width>120</width>
+    <height>20</height>
+  </widget>
+  <widget type="textentry" version="3.0.0">
+    <name>TextEntry</name>
+    <pv_name>Write</pv_name>
+    <x>146</x>
+    <y>54</y>
+    <width>124</width>
+    <height>20</height>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="label" version="2.0.0">
+    <name>Label</name>
+    <text>Read Write Single</text>
+    <x>22</x>
+    <y>78</y>
+    <width>120</width>
+    <height>20</height>
+  </widget>
+  <widget type="textentry" version="3.0.0">
+    <name>TextEntry</name>
+    <pv_name>ReadWriteSingle</pv_name>
+    <x>146</x>
+    <y>78</y>
+    <width>124</width>
+    <height>20</height>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="label" version="2.0.0">
+    <name>Label</name>
+    <text>Read Write</text>
+    <x>22</x>
+    <y>102</y>
+    <width>120</width>
+    <height>20</height>
+  </widget>
+  <widget type="textentry" version="3.0.0">
+    <name>TextEntry</name>
+    <pv_name>ReadWrite</pv_name>
+    <x>146</x>
+    <y>102</y>
+    <width>60</width>
+    <height>20</height>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="textupdate" version="2.0.0">
+    <name>TextUpdate</name>
+    <pv_name>ReadWrite_RBV</pv_name>
+    <x>210</x>
+    <y>102</y>
+    <width>60</width>
+    <height>20</height>
+    <font>
+      <font name="Default Bold" family="Liberation Sans" style="BOLD" size="14.0">
+      </font>
+    </font>
+    <horizontal_alignment>1</horizontal_alignment>
+  </widget>
+  <widget type="label" version="2.0.0">
+    <name>Label</name>
+    <text>Execute</text>
+    <x>22</x>
+    <y>126</y>
+    <width>120</width>
+    <height>20</height>
+  </widget>
+  <widget type="action_button" version="3.0.0">
+    <name>WritePV</name>
+    <pv_name>Execute</pv_name>
+    <actions>
+      <action type="write_pv">
+        <pv_name>$(pv_name)</pv_name>
+        <value>1</value>
+        <description>$(name)</description>
+      </action>
+    </actions>
+    <text>Go</text>
+    <x>146</x>
+    <y>126</y>
+    <width>124</width>
+    <height>20</height>
+    <tooltip>$(actions)</tooltip>
+  </widget>
+</display>
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 877acd39..89204e56 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -49,6 +49,20 @@ def test_format(tmp_path, helper, filename, formatter):
     )
 
 
+def test_signal_default_widgets(tmp_path, helper):
+    expected_path = HERE / "format" / "output" / "signal_default_widgets.bob"
+    input_path = HERE / "format" / "input"
+    formatter_path = input_path / "dls.bob.pvi.formatter.yaml"
+    helper.assert_cli_output_matches(
+        app,
+        expected_path,
+        "format --yaml-path " + str(input_path),
+        tmp_path / "signal_default_widgets.bob",
+        HERE / "format" / "input" / "signal_default_widgets.pvi.device.yaml",
+        formatter_path,
+    )
+
+
 def test_convert(tmp_path, helper):
     expected_path = HERE / "convert" / "output"
     input_path = HERE / "convert" / "input"