diff --git a/mods/ITEMS/REDSTONE/mcl_comparators/init.lua b/mods/ITEMS/REDSTONE/mcl_comparators/init.lua
index a8fab81d..c5cae6ad 100644
--- a/mods/ITEMS/REDSTONE/mcl_comparators/init.lua
+++ b/mods/ITEMS/REDSTONE/mcl_comparators/init.lua
@@ -43,14 +43,20 @@ end
 
 local comparator_activate = function(pos, node)
 	local def = minetest.registered_nodes[node.name]
-	minetest.swap_node(pos, { name = def.comparator_onstate, param2 = node.param2 })
+	local onstate = def.comparator_onstate
+	if onstate then
+		minetest.swap_node(pos, { name = onstate, param2 = node.param2 })
+	end
 	minetest.after(0.1, comparator_turnon , {pos = pos, node = node})
 end
 
 
 local comparator_deactivate = function(pos, node)
 	local def = minetest.registered_nodes[node.name]
-	minetest.swap_node(pos, { name = def.comparator_offstate, param2 = node.param2 })
+	local offstate = def.comparator_offstate
+	if offstate then
+		minetest.swap_node(pos, { name = offstate, param2 = node.param2 })
+	end
 	minetest.after(0.1, comparator_turnoff, {pos = pos, node = node})
 end
 
diff --git a/mods/MAPGEN/mcl_structures/init.lua b/mods/MAPGEN/mcl_structures/init.lua
index 0383c48a..0c3b1820 100644
--- a/mods/MAPGEN/mcl_structures/init.lua
+++ b/mods/MAPGEN/mcl_structures/init.lua
@@ -532,6 +532,11 @@ local function dir_to_rotation(dir)
 	return "0"
 end
 
+mcl_structures.generate_test_structure_comparator = function(pos, rotation, pr)
+	local path = minetest.get_modpath("mcl_structures").."/schematics/mcl_structures_test_structure_comparator.mts"
+	mcl_structures.place_schematic(pos, path, rotation, nil, true, nil, nil, pr)
+end
+
 mcl_structures.generate_test_structure_fireproof = function(pos, rotation, pr)
 	local path = minetest.get_modpath("mcl_structures").."/schematics/mcl_structures_test_structure_fireproof.mts"
 	mcl_structures.place_schematic(pos, path, rotation, nil, true, nil, nil, pr)
@@ -539,7 +544,7 @@ end
 
 -- Debug command
 minetest.register_chatcommand("spawnstruct", {
-	params = "desert_temple | desert_well | igloo | witch_hut | boulder | ice_spike_small | ice_spike_large | fossil | end_exit_portal | end_portal_shrine | test_structure_fireproof",
+	params = "desert_temple | desert_well | igloo | witch_hut | boulder | ice_spike_small | ice_spike_large | fossil | end_exit_portal | end_portal_shrine | test_structure_comparator | test_structure_fireproof",
 	description = S("Generate a pre-defined structure near your position."),
 	privs = {debug = true},
 	func = function(name, param)
@@ -573,6 +578,8 @@ minetest.register_chatcommand("spawnstruct", {
 			mcl_structures.generate_end_exit_portal(pos, rot, pr)
 		elseif param == "end_portal_shrine" then
 			mcl_structures.generate_end_portal_shrine(pos, rot, pr)
+		elseif param == "test_structure_comparator" then
+			mcl_structures.generate_test_structure_comparator(pos, rot, pr)
 		elseif param == "test_structure_fireproof" then
 			mcl_structures.generate_test_structure_fireproof(pos, rot, pr)
 		elseif param == "" then
diff --git a/mods/MAPGEN/mcl_structures/schematics/mcl_structures_test_structure_comparator.mts b/mods/MAPGEN/mcl_structures/schematics/mcl_structures_test_structure_comparator.mts
new file mode 100644
index 00000000..608beff9
Binary files /dev/null and b/mods/MAPGEN/mcl_structures/schematics/mcl_structures_test_structure_comparator.mts differ