diff --git a/LibSidServo/serial.c b/LibSidServo/serial.c
index d4fa65e..32c5edd 100644
--- a/LibSidServo/serial.c
+++ b/LibSidServo/serial.c
@@ -508,20 +508,20 @@ static void *mountthread(void _U_ *u){
             if(!curtime(&tnow) || (tcur = timefromstart()) < 0.) continue;
             pthread_mutex_lock(&datamutex);
             mountdata.encXposition.t = mountdata.encYposition.t = tnow;
-            mountdata.encXposition.val = c.X;
-            mountdata.encYposition.val = c.Y;
+            mountdata.encXposition.val = c.X + (drand48() - 0.5)*1e-6; // .2arcsec error
+            mountdata.encYposition.val = c.Y + (drand48() - 0.5)*1e-6;
             //DBG("t=%g, X=%g, Y=%g", tnow, c.X.val, c.Y.val);
             if(tcur - oldmt > Conf.MountReqInterval){
                 oldmillis = mountdata.millis = (uint32_t)((tcur - tstart) * 1e3);
                 mountdata.motYposition.t = mountdata.motXposition.t = tnow;
                 if(xst == ST_MOVE)
                     mountdata.motXposition.val = c.X + (c.X - mountdata.motXposition.val)*(drand48() - 0.5)/100.;
-                else
-                    mountdata.motXposition.val = c.X;
+                //else
+                //    mountdata.motXposition.val = c.X;
                 if(yst == ST_MOVE)
                     mountdata.motYposition.val = c.Y + (c.Y - mountdata.motYposition.val)*(drand48() - 0.5)/100.;
-                else
-                    mountdata.motYposition.val = c.Y;
+                //else
+                //    mountdata.motYposition.val = c.Y;
                 oldmt = tcur;
             }else mountdata.millis = oldmillis;
             chkModStopped(&Xprev, c.X, &xcnt, &mountdata.Xstate);