diff --git a/scp.c b/scp.c
index 9195c340..acd2570e 100644
--- a/scp.c
+++ b/scp.c
@@ -326,7 +326,6 @@
 #if defined (SIM_ASYNCH_IO)
 pthread_mutex_t sim_asynch_lock = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t sim_asynch_wake = PTHREAD_COND_INITIALIZER;
-pthread_mutex_t sim_idle_lock = PTHREAD_MUTEX_INITIALIZER;
 
 pthread_mutex_t sim_timer_lock     = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t sim_timer_wake      = PTHREAD_COND_INITIALIZER;
diff --git a/sim_defs.h b/sim_defs.h
index 24ead23e..f1d550fc 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -1063,7 +1063,6 @@ struct MEMFILE {
 
 extern pthread_mutex_t sim_asynch_lock;
 extern pthread_cond_t sim_asynch_wake;
-extern pthread_mutex_t sim_idle_lock;
 extern pthread_mutex_t sim_timer_lock;
 extern pthread_cond_t sim_timer_wake;
 extern t_bool sim_timer_event_canceled;
@@ -1176,7 +1175,6 @@ extern int32 sim_asynch_inst_latency;
     do {                                                          \
       pthread_mutex_destroy(&sim_asynch_lock);                    \
       pthread_cond_destroy(&sim_asynch_wake);                     \
-      pthread_mutex_destroy(&sim_idle_lock);                      \
       pthread_mutex_destroy(&sim_timer_lock);                     \
       pthread_cond_destroy(&sim_timer_wake);                      \
       pthread_mutex_destroy(&sim_tmxr_poll_lock);                 \
@@ -1226,7 +1224,6 @@ extern int32 sim_asynch_inst_latency;
     do {                                                          \
       pthread_mutex_destroy(&sim_asynch_lock);                    \
       pthread_cond_destroy(&sim_asynch_wake);                     \
-      pthread_mutex_destroy(&sim_idle_lock);                      \
       pthread_mutex_destroy(&sim_timer_lock);                     \
       pthread_cond_destroy(&sim_timer_wake);                      \
       pthread_mutex_destroy(&sim_tmxr_poll_lock);                 \
diff --git a/sim_timer.c b/sim_timer.c
index 2094499d..c89e93d5 100644
--- a/sim_timer.c
+++ b/sim_timer.c
@@ -244,27 +244,18 @@ int stat;
 clock_gettime(CLOCK_REALTIME, &done_time);
 done_time.tv_sec += (msec/1000);
 done_time.tv_nsec += 1000000*(msec%1000);
-if (done_time.tv_nsec > 1000000000) {
+if (done_time.tv_nsec >= 1000000000) {
   done_time.tv_sec += done_time.tv_nsec/1000000000;
   done_time.tv_nsec = done_time.tv_nsec%1000000000;
   }
-pthread_mutex_lock (&sim_idle_lock);
+pthread_mutex_lock (&sim_asynch_lock);
 sim_idle_wait = TRUE;
-stat = pthread_cond_timedwait (&sim_asynch_wake, &sim_idle_lock, &done_time);
-if (stat == 0)
-  sim_asynch_check = 0;                 /* force check of asynch queue now */
-else
-  if (stat == ETIMEDOUT)
+if (pthread_cond_timedwait (&sim_asynch_wake, &sim_asynch_lock, &done_time))
     timedout = TRUE;
-  else {
-    char ans[32];
-
-    fprintf (stderr, "sim_idle_ms_sleep(%u): pthread_cond_timedwait() return %d - %s\r\n", msec, stat, strerror (stat));
-    read_line_p ("Hit Return to exit: ", ans, sizeof (ans) - 1, stdin);
-    abort ();
-    }
+else
+    sim_asynch_check = 0;                 /* force check of asynch queue now */
 sim_idle_wait = FALSE;
-pthread_mutex_unlock (&sim_idle_lock);
+pthread_mutex_unlock (&sim_asynch_lock);
 if (!timedout) {
     AIO_UPDATE_QUEUE;
     }