Preventing double RTM calls - but still hangs

scorch.asm

@@ -88,6 +88,7 @@
     ;.zpvar dliX             .byte
     ;.zpvar dliY             .byte
 	.zpvar sfx_effect .byte
+	.zpvar RMT_VBL_Runin	.byte
 ;-------------- 
 
 	displayposition = modify
@@ -157,6 +158,7 @@ FirstSTART
     sta sfx_effect
 
     lda #0
+	sta RMT_VBL_Runin
     jsr RmtSongSelect
 
     VMAIN VBLinterrupt,7  		;jsr SetVBL
@@ -1152,8 +1154,10 @@ itsPAL
     ; pressTimer is trigger tick counter. always 50 ticks / s
     bit:smi:inc pressTimer ; timer halted if >127. max time measured 2.5 s
 
-    
+	lda RMT_VBL_Runin
+	bne SkipRMTVBL
     ; ------- RMT -------
+	inc RMT_VBL_Runin
 	lda sfx_effect
     bmi lab2
     asl @                       ; * 2
@@ -1167,8 +1171,10 @@ itsPAL
     sta sfx_effect              ;reinit value
 lab2
     jsr RASTERMUSICTRACKER+3    ;1 play
+	lda #0
+	sta RMT_VBL_Runin
     ; ------- RMT -------
-	   
+SkipRMTVBL	   
 exitVBL
     ply
     plx