diff --git a/src/emu/validity.c b/src/emu/validity.c
index dbd841c0a7d..d3f57a3fb8d 100644
--- a/src/emu/validity.c
+++ b/src/emu/validity.c
@@ -1327,6 +1327,7 @@ static int validate_inputs(int drivnum, const machine_config *config, const inpu
 	for (port = *portlistptr; port != NULL; port = port->next)
 		for (field = port->fieldlist; field != NULL; field = field->next)
 		{
+			const input_setting_config *setting;
 			int strindex = 0;
 
 			/* verify analog inputs */
@@ -1381,6 +1382,39 @@ static int validate_inputs(int drivnum, const machine_config *config, const inpu
 				/* look up the string and print an error if default strings are not used */
 				strindex = get_defstr_index(field->name, driver, &error);
 			}
+			
+			/* verify conditions on the field */
+			if (field->condition.tag != NULL)
+			{
+				/* find a matching port */
+				for (scanport = *portlistptr; scanport != NULL; scanport = scanport->next)
+					if (scanport->tag != NULL && strcmp(field->condition.tag, scanport->tag) == 0)
+						break;
+				
+				/* if none, error */
+				if (scanport == NULL)
+				{
+					mame_printf_error("%s: %s has a condition referencing non-existent input port tag \"%s\"\n", driver->source_file, driver->name, field->condition.tag);
+					error = TRUE;
+				}
+			}
+			
+			/* verify conditions on the settings */
+			for (setting = field->settinglist; setting != NULL; setting = setting->next)
+				if (setting->condition.tag != NULL)
+				{
+					/* find a matching port */
+					for (scanport = *portlistptr; scanport != NULL; scanport = scanport->next)
+						if (scanport->tag != NULL && strcmp(setting->condition.tag, scanport->tag) == 0)
+							break;
+					
+					/* if none, error */
+					if (scanport == NULL)
+					{
+						mame_printf_error("%s: %s has a condition referencing non-existent input port tag \"%s\"\n", driver->source_file, driver->name, setting->condition.tag);
+						error = TRUE;
+					}
+				}
 		}
 
 #ifdef MESS
diff --git a/src/mame/drivers/asteroid.c b/src/mame/drivers/asteroid.c
index 89d6a046e49..e4b3f08775f 100644
--- a/src/mame/drivers/asteroid.c
+++ b/src/mame/drivers/asteroid.c
@@ -397,14 +397,14 @@ static INPUT_PORTS_START( asterock )
 	PORT_DIPSETTING (	0x00, DEF_STR( Normal ) )
 	PORT_DIPSETTING (	0x20, "Special" )
 	PORT_DIPNAME( 0xc0, 0x80, DEF_STR( Coinage ) )					PORT_DIPLOCATION("SW:7,8")
-	PORT_DIPSETTING (	0xc0, DEF_STR( 2C_1C ) )					PORT_CONDITION("DSW",0x20,PORTCOND_EQUALS,0x00)
-	PORT_DIPSETTING (	0x80, DEF_STR( 1C_1C ) )					PORT_CONDITION("DSW",0x20,PORTCOND_EQUALS,0x00)
-	PORT_DIPSETTING (	0x40, DEF_STR( 1C_2C ) )					PORT_CONDITION("DSW",0x20,PORTCOND_EQUALS,0x00)
-//  PORT_DIPSETTING (   0x00, DEF_STR( 1C_1C ) )                    PORT_CONDITION("DSW",0x20,PORTCOND_EQUALS,0x00)
-	PORT_DIPSETTING (	0xc0, "Coin A 2/1 Coin B 2/1 Coin C 1/1" )	PORT_CONDITION("DSW",0x20,PORTCOND_NOTEQUALS,0x00)
-	PORT_DIPSETTING (	0x80, "Coin A 1/1 Coin B 1/1 Coin C 1/2" )	PORT_CONDITION("DSW",0x20,PORTCOND_NOTEQUALS,0x00)
-	PORT_DIPSETTING (	0x40, "Coin A 1/2 Coin B 1/2 Coin C 1/4" )	PORT_CONDITION("DSW",0x20,PORTCOND_NOTEQUALS,0x00)
-//  PORT_DIPSETTING (   0x00, "Coin A 1/1 Coin B 1/1 Coin C 1/2" )  PORT_CONDITION("DSW",0x20,PORTCOND_NOTEQUALS,0x00)
+	PORT_DIPSETTING (	0xc0, DEF_STR( 2C_1C ) )					PORT_CONDITION("DSW1",0x20,PORTCOND_EQUALS,0x00)
+	PORT_DIPSETTING (	0x80, DEF_STR( 1C_1C ) )					PORT_CONDITION("DSW1",0x20,PORTCOND_EQUALS,0x00)
+	PORT_DIPSETTING (	0x40, DEF_STR( 1C_2C ) )					PORT_CONDITION("DSW1",0x20,PORTCOND_EQUALS,0x00)
+//  PORT_DIPSETTING (   0x00, DEF_STR( 1C_1C ) )                    PORT_CONDITION("DSW1",0x20,PORTCOND_EQUALS,0x00)
+	PORT_DIPSETTING (	0xc0, "Coin A 2/1 Coin B 2/1 Coin C 1/1" )	PORT_CONDITION("DSW1",0x20,PORTCOND_NOTEQUALS,0x00)
+	PORT_DIPSETTING (	0x80, "Coin A 1/1 Coin B 1/1 Coin C 1/2" )	PORT_CONDITION("DSW1",0x20,PORTCOND_NOTEQUALS,0x00)
+	PORT_DIPSETTING (	0x40, "Coin A 1/2 Coin B 1/2 Coin C 1/4" )	PORT_CONDITION("DSW1",0x20,PORTCOND_NOTEQUALS,0x00)
+//  PORT_DIPSETTING (   0x00, "Coin A 1/1 Coin B 1/1 Coin C 1/2" )  PORT_CONDITION("DSW1",0x20,PORTCOND_NOTEQUALS,0x00)
 INPUT_PORTS_END