diff --git a/src/mame/drivers/unkhorse.cpp b/src/mame/drivers/unkhorse.cpp
index 5773eca2356..e04b0b9e009 100644
--- a/src/mame/drivers/unkhorse.cpp
+++ b/src/mame/drivers/unkhorse.cpp
@@ -46,7 +46,6 @@ public:
 
 	DECLARE_READ8_MEMBER(input_r);
 	DECLARE_WRITE8_MEMBER(output_w);
-	DECLARE_WRITE_LINE_MEMBER(timer_out);
 
 	virtual void machine_start() override;
 	UINT32 screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);