diff --git a/src/emu/cpu/mb88xx/mb88xx.c b/src/emu/cpu/mb88xx/mb88xx.c
index 0972d89901c..1dd813f06ad 100644
--- a/src/emu/cpu/mb88xx/mb88xx.c
+++ b/src/emu/cpu/mb88xx/mb88xx.c
@@ -247,7 +247,7 @@ static int pla( mb88_state *cpustate, int inA, int inB )
 static void set_irq_line(mb88_state *cpustate, int state)
 {
 	/* on falling edge trigger interrupt */
-	if ( (cpustate->pio & 0x04) && cpustate->nf == 0 && state != CLEAR_LINE )
+	if ( (cpustate->pio & 0x04) && state != CLEAR_LINE )
 	{
 		cpustate->pending_interrupt |= INT_CAUSE_EXTERNAL;
 	}