one

code/game/objects/items/devices/geiger_counter.dm

@@ -192,13 +192,15 @@
 	update_icon()
 
 /obj/item/geiger_counter/emag_act(mob/user)
+	. = ..()
 	if(obj_flags & EMAGGED)
 		return
 	if(scanning)
 		to_chat(user, "<span class='warning'>Turn off [src] before you perform this action!</span>")
-		return 0
+		return
 	to_chat(user, "<span class='warning'>You override [src]'s radiation storing protocols. It will now generate small doses of radiation, and stored rads are now projected into creatures you scan.</span>")
 	obj_flags |= EMAGGED
+	return TRUE
 
 /obj/item/geiger_counter/cyborg
 	var/datum/component/mobhook

code/game/objects/items/devices/lightreplacer.dm

@@ -149,9 +149,11 @@
 		to_chat(user, "<span class='notice'>You fill \the [src] with lights from \the [S]. " + status_string() + "</span>")
 
 /obj/item/lightreplacer/emag_act()
+	. = ..()
 	if(obj_flags & EMAGGED)
 		return
 	Emag()
+	return TRUE
 
 /obj/item/lightreplacer/attack_self(mob/user)
 	to_chat(user, status_string())

code/game/objects/items/devices/megaphone.dm

@@ -26,11 +26,13 @@
 		return voicespan
 
 /obj/item/megaphone/emag_act(mob/user)
+	. = ..()
 	if(obj_flags & EMAGGED)
 		return
 	to_chat(user, "<span class='warning'>You overload \the [src]'s voice synthesizer.</span>")
 	obj_flags |= EMAGGED
 	voicespan = list(SPAN_REALLYBIG, "userdanger")
+	return TRUE
 
 /obj/item/megaphone/sec
 	name = "security megaphone"