diff --git a/src/gui/doAction.cpp b/src/gui/doAction.cpp
index 5b3020d2a..17b515b2f 100644
--- a/src/gui/doAction.cpp
+++ b/src/gui/doAction.cpp
@@ -537,7 +537,15 @@ void FurnaceGUI::doAction(int what) {
         showError("too many instruments!");
       } else {
         if (settings.blankIns) {
-          memset(&e->song.ins[curIns]->fm,0,sizeof(DivInstrumentFM));
+          e->song.ins[curIns]->fm.fb=0;
+          for (int i=0; i<4; i++) {
+            e->song.ins[curIns]->fm.op[i]=DivInstrumentFM::Operator();
+            e->song.ins[curIns]->fm.op[i].ar=31;
+            e->song.ins[curIns]->fm.op[i].dr=31;
+            e->song.ins[curIns]->fm.op[i].rr=15;
+            e->song.ins[curIns]->fm.op[i].tl=127;
+            e->song.ins[curIns]->fm.op[i].dt=3;
+          }
         }
         wantScrollList=true;
         MARK_MODIFIED;