diff --git a/src/spicelib/analysis/dctran.c b/src/spicelib/analysis/dctran.c
index ff9dee3e7..9716e9fa3 100644
--- a/src/spicelib/analysis/dctran.c
+++ b/src/spicelib/analysis/dctran.c
@@ -80,9 +80,6 @@ DCtran(CKTcircuit *ckt,
 #ifdef WANT_SENSE2
     int save, save2, size;
     long save1;
-#ifdef SENSDEBUG
-    FILE *outsen;
-#endif /* SENSDEBUG */
 #endif
     int save_order;
     long save_mode;
@@ -484,9 +481,6 @@ DCtran(CKTcircuit *ckt,
 #ifdef WANT_SENSE2
         if(ckt->CKTsenInfo && (ckt->CKTsenInfo->SENmode & TRANSEN)){
             ckt->CKTsenInfo->SENmode = save;
-#ifdef SENSDEBUG
-            fclose(outsen);
-#endif /* SENSDEBUG */
         }
 #endif
         return(OK);
diff --git a/src/spicelib/devices/bjt/bjtsupd.c b/src/spicelib/devices/bjt/bjtsupd.c
index f2551e6c9..f76ef8f71 100644
--- a/src/spicelib/devices/bjt/bjtsupd.c
+++ b/src/spicelib/devices/bjt/bjtsupd.c
@@ -55,9 +55,8 @@ BJTsUpdate(GENmodel *inModel, CKTcircuit *ckt)
             sxpbx = 0;
 #ifdef SENSDEBUG
             printf("senupdate Instance name: %s\n",here->BJTname);
-            printf("iparmno = %d,CKTag[0] = %.2e,CKTag[1] = %.2e\n",
-                    iparmno,ckt->CKTag[0],ckt->CKTag[1]);
-
+            printf("CKTag[0] = %.2e,CKTag[1] = %.2e\n",
+                    ckt->CKTag[0],ckt->CKTag[1]);
             printf("capbe = %.7e\n",here->BJTcapbe);
             printf("capbc = %.7e\n",here->BJTcapbc);
             printf("capsub = %.7e\n",here->BJTcapsub);
diff --git a/src/unsupported/cktsenup.c b/src/unsupported/cktsenup.c
index cbfd42e8a..0ce1acfbd 100644
--- a/src/unsupported/cktsenup.c
+++ b/src/unsupported/cktsenup.c
@@ -26,7 +26,7 @@ CKTsenUpdate(CKTcircuit *ckt)
     int error;
 
     for (i = 0; i < DEVmaxnum; i++)
-        if (DEVices[i]->DEVsenUpdate && ckt->CKThead[i]) {
+        if (DEVices[i] && DEVices[i]->DEVsenUpdate && ckt->CKThead[i]) {
             error = DEVices[i]->DEVsenUpdate (ckt->CKThead[i], ckt);
             if (error)
                 return error;
diff --git a/src/unsupported/cktsncom.c b/src/unsupported/cktsncom.c
index 747bc3452..5fc0b905e 100644
--- a/src/unsupported/cktsncom.c
+++ b/src/unsupported/cktsncom.c
@@ -17,6 +17,22 @@ Author: 1985 Thomas L. Quarles
 #include "ngspice/trandefs.h"
 #include "ngspice/suffix.h"
 
+// #include "../maths/sparse/spdefs.h"
+//
+// this include file from `sparse' is incompatible
+//   with the rest of ngspice
+// so we can unfortunatly not include here
+// instead we cheat a bit and
+// introduce the opaque struct MatrixElement here
+//   (only the first struct members which are of importance to us)
+
+struct  MatrixElement
+{
+    double   Real;
+    double   Imag;
+    // ...
+};
+
 
 int
 CKTsenComp(CKTcircuit *ckt)
@@ -66,14 +82,14 @@ CKTsenComp(CKTcircuit *ckt)
 
         for (row = 1; row <= size; row++) {
             rowe = CKTnodName(ckt, row);
-            if (strcmp("4", rowe) == 0) {
+//          if (strcmp("4", rowe) == 0) {
                 for (col = 1; col <= info->SENparms; col++) {
                     printf("\t");
                     printf("Sap(%s,%d) = %.5e\t", rowe, col,
                            info->SEN_Sap[row][col]);
                 }
                 printf("\n\n");
-            }
+//          }
         }
 
         printf("  RHS matrix   :\n");
@@ -88,11 +104,13 @@ CKTsenComp(CKTcircuit *ckt)
 
         printf("      Jacobian  matrix :\n");
         for (row = 1; row <= size; row++) {
-            for (col = 1; col <= size; col++)
-                if (elt = SMPfindElt(ckt->CKTmatrix, row , col , 0))
-                    printf("%.7e ", elt->SMPvalue);
+            for (col = 1; col <= size; col++) {
+                elt = SMPfindElt(ckt->CKTmatrix, row , col , 0);
+                if (elt)
+                    printf("%.7e ", elt->Real);
                 else
                     printf("0.0000000e+00 ");
+            }
             printf("\n");
         }
 #endif
@@ -154,9 +172,10 @@ CKTsenComp(CKTcircuit *ckt)
         printf("      Jacobian  matrix for AC :\n");
         for (row = 1; row <= size; row++) {
             for (col = 1; col <= size; col++) {
-                if (elt = SMPfindElt(ckt->CKTmatrix, row , col , 0)) {
-                    printf("%.7e ", elt->SMPvalue);
-                    printf("+j%.7e\t", elt->SMPiValue);
+                elt = SMPfindElt(ckt->CKTmatrix, row , col , 0);
+                if (elt) {
+                    printf("%.7e ", elt->Real);
+                    printf("+j%.7e\t", elt->Imag);
                 } else{
                     printf("0.0000000e+00 ");
                     printf("+j0.0000000e+00\t");
diff --git a/src/unsupported/cktsnld.c b/src/unsupported/cktsnld.c
index a96ede9aa..7afeaf3a5 100644
--- a/src/unsupported/cktsnld.c
+++ b/src/unsupported/cktsnld.c
@@ -41,7 +41,7 @@ CKTsenLoad(CKTcircuit *ckt)
                 ckt->CKTsenInfo->SEN_RHS[row][col] = 0;
 
         for (i = 0; i < DEVmaxnum; i++)
-            if (DEVices[i]->DEVsenLoad && ckt->CKThead[i]) {
+            if (DEVices[i] && DEVices[i]->DEVsenLoad && ckt->CKThead[i]) {
                 error = DEVices[i]->DEVsenLoad (ckt->CKThead[i], ckt);
                 if (error)
                     return error;
@@ -56,7 +56,7 @@ CKTsenLoad(CKTcircuit *ckt)
             }
 
         for (i = 0; i < DEVmaxnum; i++)
-            if (DEVices[i]->DEVsenAcLoad && ckt->CKThead[i]) {
+            if (DEVices[i] && DEVices[i]->DEVsenAcLoad && ckt->CKThead[i]) {
                 error = DEVices[i]->DEVsenAcLoad (ckt->CKThead[i], ckt);
                 if (error)
                     return error;
diff --git a/src/unsupported/cktsnprt.c b/src/unsupported/cktsnprt.c
index 1a2bc224e..c0a6801c8 100644
--- a/src/unsupported/cktsnprt.c
+++ b/src/unsupported/cktsnprt.c
@@ -25,6 +25,6 @@ CKTsenPrint(CKTcircuit *ckt)
     int i;
 
     for (i = 0; i < DEVmaxnum; i++)
-        if (DEVices[i]->DEVsenPrint && ckt->CKThead[i])
+        if (DEVices[i] && DEVices[i]->DEVsenPrint && ckt->CKThead[i])
             DEVices[i]->DEVsenPrint (ckt->CKThead[i], ckt);
 }
diff --git a/src/unsupported/cktsnset.c b/src/unsupported/cktsnset.c
index 551697da0..d2984acce 100644
--- a/src/unsupported/cktsnset.c
+++ b/src/unsupported/cktsnset.c
@@ -36,7 +36,7 @@ CKTsenSetup(CKTcircuit *ckt)
     info->SENparms = 0;
 
     for (i = 0; i < DEVmaxnum; i++)
-        if (DEVices[i]->DEVsenSetup && ckt->CKThead[i]) {
+        if (DEVices[i] && DEVices[i]->DEVsenSetup && ckt->CKThead[i]) {
             error = DEVices[i]->DEVsenSetup (info, ckt->CKThead[i]);
             if (error)
                 return error;
diff --git a/src/unsupported/snstart.c b/src/unsupported/snstart.c
index b251f807d..26fc9d115 100644
--- a/src/unsupported/snstart.c
+++ b/src/unsupported/snstart.c
@@ -25,8 +25,7 @@ SENstartup(CKTcircuit *ckt, int restart)
     GENinstance *fast;
 
     if (restart) {
-        fprintf(stderr, "unsupported code, (SENstartup), doesn't support restart\n");
-        exit(1);
+        fprintf(stdout, "Sensitivity-2 analysis: unsupported code\n");
     }
 
 #ifdef SENSDEBUG
@@ -37,7 +36,7 @@ SENstartup(CKTcircuit *ckt, int restart)
     ckt->CKTsenInfo->SENpertfac = 1e-4;
     ckt->CKTsenInfo->SENinitflag = ON; /* allocate memory in NIsenReinit */
 
-    parmtemp.iValue = 1;
+    parmtemp.rValue = 1.0;
 
     for (i = 0; i < ckt->CKTsenInfo->SENnumVal; i++) {
         type = -1;
@@ -49,6 +48,10 @@ SENstartup(CKTcircuit *ckt, int restart)
         if (err != OK)
             return err;
 
+#ifdef SENSDEBUG
+        printf("SENstartup Instance: %s Design parameter: %s\n", ckt->CKTsenInfo->SENdevices[i],
+                                                                 ckt->CKTsenInfo->SENparmNames[i]);
+#endif
         err = CKTpName(
             ckt->CKTsenInfo->SENparmNames[i],
             &parmtemp, ckt, type,