diff --git a/custom_components/localthings/registry/capabilities/microwave.py b/custom_components/localthings/registry/capabilities/microwave.py
index 7dcb7f5..4e815ad 100644
--- a/custom_components/localthings/registry/capabilities/microwave.py
+++ b/custom_components/localthings/registry/capabilities/microwave.py
@@ -21,7 +21,12 @@ different from an oven, and defined fresh here:
   * Lamp: this family's option-array token is bare 'Lamp' (issue #137's
     'Lamp_Off'), not oven.py's 'UpperLamp' -- and it's genuinely absent on
     the combi dump (issue #121), so it's gated with exists_fn rather than
-    assumed universal like oven.py's lamp switch.
+    assumed universal like oven.py's lamp switch. Issue #137's dump only
+    ever showed 'Off', so 'On' was a guess at the paired value; issue #152's
+    ME7500D dump is the first to show a real non-Off value, and it's 'High'
+    (a brightness level, not literally 'On') -- the switch now treats any
+    non-Off/non-None value as "on" for reads, and writes back 'High'/'Off'
+    (the two confirmed tokens) rather than the never-confirmed 'On'.
 
 Note: cooking-mode writes are unproven here, same caveat as oven.py's
 OVEN_MODE -- exposed as a SelectDesc for fidelity, first real-world write
@@ -132,8 +137,12 @@ def _lamp_write(p, rep, href=None):
         return None
     if not rep.get('x.com.samsung.da.options'):
         return None
+    # 'High' and 'Off' are the two tokens actually confirmed on live dumps
+    # (issues #137/#152) -- 'On' has never been observed and the device
+    # likely doesn't recognize it (see module docstring).
+    token = 'High' if p == 'On' else 'Off'
     return ['mode', 'vs', '0'], {
-        'x.com.samsung.da.options': option_write('Lamp', p),
+        'x.com.samsung.da.options': option_write('Lamp', token),
     }
 
 
@@ -189,7 +198,7 @@ MICROWAVE_MODE = Capability(
         SwitchDesc(key='lamp', field='x.com.samsung.da.options',
                    icon='mdi:track-light',
                    exists_fn=_lamp_exists,
-                   value_fn=lambda opts: option_value(opts, 'Lamp') == 'On',
+                   value_fn=lambda opts: option_value(opts, 'Lamp') not in (None, 'Off'),
                    write_fn=_lamp_write),
     ),
 )
diff --git a/tests/test_microwave_capabilities.py b/tests/test_microwave_capabilities.py
index 05f0b91..5629322 100644
--- a/tests/test_microwave_capabilities.py
+++ b/tests/test_microwave_capabilities.py
@@ -165,13 +165,28 @@ def test_lamp_gated_present_when_lamp_option_reported():
 
 
 def test_lamp_write_is_single_token():
+    """issue #152: the device has never been observed accepting 'On' --
+    only 'High'/'Off' -- so the switch's "on" write uses 'High'."""
     desc = next(e for e in microwave.MICROWAVE_MODE.entities if e.key == 'lamp')
     rep = {'x.com.samsung.da.options': ['Lamp_Off']}
     path, body = desc.write_fn('On', rep)
     assert path == ['mode', 'vs', '0']
-    assert body == {'x.com.samsung.da.options': ['Lamp_On']}
+    assert body == {'x.com.samsung.da.options': ['Lamp_High']}
 
 
 def test_lamp_write_requires_existing_options():
     desc = next(e for e in microwave.MICROWAVE_MODE.entities if e.key == 'lamp')
     assert desc.write_fn('On', {}) is None
+
+
+def test_lamp_reads_off_as_false():
+    desc = next(e for e in microwave.MICROWAVE_MODE.entities if e.key == 'lamp')
+    assert desc.value_fn(['Lamp_Off']) is False
+
+
+def test_lamp_reads_any_non_off_level_as_true():
+    """issue #152's ME7500D reports 'Lamp_High', not the binary 'Lamp_On'
+    #137's dump implied -- any non-Off/non-absent value must read as on, not
+    just a literal 'On'."""
+    desc = next(e for e in microwave.MICROWAVE_MODE.entities if e.key == 'lamp')
+    assert desc.value_fn(['Lamp_High']) is True