diff --git a/pt3_lib/interrupt_handler.s b/pt3_lib/interrupt_handler.s
index 25dc329d..d8a4a80f 100644
--- a/pt3_lib/interrupt_handler.s
+++ b/pt3_lib/interrupt_handler.s
@@ -13,7 +13,7 @@
 TIME_OFFSET	EQU	13
 
 interrupt_handler:
-;	pha			; save A				; 3
+	pha			; save A				; 3
 				; A is saved in $45 by firmware
 	txa
 	pha			; save X
@@ -145,8 +145,12 @@ exit_interrupt:
 	tay			; restore Y
 	pla
 	tax			; restore X
+	pla			; restore a				; 4
+
+
+	; on II+/IIe (but not IIc) we need to do this?
+interrupt_smc:
 	lda	$45		; restore A
-;	pla			; restore a				; 4
 
 	rti			; return from interrupt			; 6
 
diff --git a/pt3_lib/pt3_test.s b/pt3_lib/pt3_test.s
index 479510b6..ef732a71 100644
--- a/pt3_lib/pt3_test.s
+++ b/pt3_lib/pt3_test.s
@@ -27,11 +27,39 @@ pt3_setup:
 
 	lda	$FBB3           ; IIe and newer is $06
 	cmp	#6
-	beq	apple_iie
+	beq	apple_iie_or_newer
 
 	lda	#1		; set if older than a IIe
 	sta	apple_ii
-apple_iie:
+	jmp	done_apple_detect
+apple_iie_or_newer:
+	lda	$FBC0		; 0 on a IIc
+	bne	done_apple_detect
+apple_iic:
+	; activate IIc mockingboard?
+	; this might only be necessary to allow detection
+	; I get the impression the Mockingboard 4c activates
+	; when you access any of the 6522 ports in Slot 4
+	lda	#$ff
+	sta	$C403
+	sta	$C404
+
+	; bypass the firmware interrupt handler
+	; should we do this on IIe too? probably faster
+
+	sei				; disable interrupts
+	lda	$c08b			; disable ROM (enable language card)
+	lda	$c08b
+	lda	#<interrupt_handler
+	sta	$fffe
+	lda	#>interrupt_handler
+	sta	$ffff
+
+	lda	#$EA			; nop out the "lda $45" in the irq hand
+	sta	interrupt_smc
+	sta	interrupt_smc+1
+
+done_apple_detect:
 
 	;===============
 	; init variables
diff --git a/pt3_player/interrupt_handler.s b/pt3_player/interrupt_handler.s
index e48d7716..6f059cc8 100644
--- a/pt3_player/interrupt_handler.s
+++ b/pt3_player/interrupt_handler.s
@@ -288,14 +288,12 @@ quiet_exit:
 done_key:
 exit_interrupt:
 
-;	pla			; restore a				; 4
-
 	pla
 	tay			; restore Y
 	pla
 	tax			; restore X
 	lda	$45		; restore A
-
+;	pla			; restore a				; 4
 
 	rti			; return from interrupt			; 6