diff --git a/3B2/3b2_cpu.c b/3B2/3b2_cpu.c
index c41e06eb..b4de1283 100644
--- a/3B2/3b2_cpu.c
+++ b/3B2/3b2_cpu.c
@@ -3455,7 +3455,7 @@ static void cpu_calc_ints()
         cpu_int_ipl = cpu_int_vec = CPU_ID_IF_IPL;
     } else if ((csr_data & CSRUART) || (csr_data & CSRDMA)) {
         cpu_int_ipl = cpu_int_vec = CPU_IU_DMA_IPL;
-    } else if (csr_data & CSRCLK) {
+    } else if ((csr_data & CSRCLK) || (csr_data & CSRTIMO)) {
         cpu_int_ipl = cpu_int_vec = CPU_TMR_IPL;
     } else {
         cpu_int_ipl = cpu_int_vec = 0;
diff --git a/3B2/3b2_sysdev.c b/3B2/3b2_sysdev.c
index 1414992c..58c046a7 100644
--- a/3B2/3b2_sysdev.c
+++ b/3B2/3b2_sysdev.c
@@ -433,8 +433,14 @@ REG timer_reg[] = {
     { NULL }
 };
 
+MTAB timer_mod[] = {
+    { MTAB_XTD|MTAB_VDV|MTAB_VALR|MTAB_NC, 0, NULL, "SHUTDOWN",
+      &timer_set_shutdown, NULL, NULL, "Soft Power Shutdown" },
+    { 0 }
+};
+
 DEVICE timer_dev = {
-    "TIMER", timer_unit, timer_reg, NULL,
+    "TIMER", timer_unit, timer_reg, timer_mod,
     1, 16, 8, 4, 16, 32,
     NULL, NULL, &timer_reset,
     NULL, NULL, NULL, NULL,
@@ -468,6 +474,23 @@ t_stat timer_reset(DEVICE *dptr) {
     return SCPE_OK;
 }
 
+t_stat timer_set_shutdown(UNIT *uptr, int32 val, CONST char* cptr, void* desc)
+{
+    struct timer_ctr *sanity = timer_unit[0].tmr;
+
+    sim_debug(EXECUTE_MSG, &timer_dev,
+              "[%08x] Setting sanity timer to 0 for shutdown.\n", R[NUM_PC]);
+
+    sanity->val = 0;
+    csr_data &= ~CSRCLK;
+    csr_data |= CSRTIMO;
+
+    return SCPE_OK;
+}
+
+/*
+ * Sanity Timer
+ */
 t_stat timer0_svc(UNIT *uptr)
 {
     struct timer_ctr *ctr;
@@ -486,6 +509,9 @@ t_stat timer0_svc(UNIT *uptr)
     return SCPE_OK;
 }
 
+/*
+ * Interval Timer
+ */
 t_stat timer1_svc(UNIT *uptr)
 {
     struct timer_ctr *ctr;
@@ -505,6 +531,9 @@ t_stat timer1_svc(UNIT *uptr)
     return SCPE_OK;
 }
 
+/*
+ * Bus Timeout Timer
+ */
 t_stat timer2_svc(UNIT *uptr)
 {
     struct timer_ctr *ctr;
diff --git a/3B2/3b2_sysdev.h b/3B2/3b2_sysdev.h
index 63394a8f..8f749150 100644
--- a/3B2/3b2_sysdev.h
+++ b/3B2/3b2_sysdev.h
@@ -69,6 +69,7 @@ void timer_write(uint32 pa, uint32 val, size_t size);
 t_stat timer0_svc(UNIT *uptr);
 t_stat timer1_svc(UNIT *uptr);
 t_stat timer2_svc(UNIT *uptr);
+t_stat timer_set_shutdown(UNIT *uptr, int32 val, CONST char *cptr, void *desc);
 
 /* CSR */
 t_stat csr_svc(UNIT *uptr);