TimerTask stopped without Exception

Hi
My tomcat Server communicates with an external device with TCP
Sockets. The call is from a TimerTask initalized as follows:

        t17 = new Timer();
        t17.schedule(new ExternalTimerTask(fky_id), dd, 500);

The TT see below:

 public void run() {
    try {
      try {
        sisag.komm.CSisCad SisCad = new sisag.komm.CSisCad(fky_id);
        String sErrorReceive = "";
        sErrorReceive = SisCad.recvString(fky_id);
        if(sErrorReceive.startsWith("1") ||
sErrorReceive.startsWith("0")) {

            sTemp = sErrorReceive.substring(0,8);
            i0 = java.lang.Integer.parseInt(sTemp,2);

            String sAktuell = ""+i0+""+i3+""+i4+""+i5;
            if(sLastZustand.equals("")|| !
sLastZustand.equals(sAktuell)) {
               //Update database
               sLastZustand=sAktuell;
            }
        } else {
             System.out.println("data not valid:"+sErrorReceive);
        }
      } catch(Exception e) {
        System.out.println("Exception in SisCadTimerTask: " + e);
      }

      Thread.sleep(100);

    } catch (InterruptedException e) {
       System.out.println("InterruptedException in SisCadTimerTask: "
+ e);
    }
  } // end of run

and the called Socket looks like:
    public String recvString(String region) {
        try {
              skt.connect (new InetSocketAddress(sIP, iPort),
iTimeOut);
              if (skt.isConnected()) {
                  sReturn = "online";
                  sData = "";
                  BufferedReader in = new BufferedReader(new
InputStreamReader(skt.getInputStream()));
                  if (true) {
                     sData += in.readLine(); // readLine: Read one
line and output it
                     sReturn = sData;
                  }
                  in.close();
              }
              else {
                  System.out.println("can't open socket");
              }
              skt.close();

        } catch (Exception e) {
           System.out.println("Receive1 Exception: "+e);
        }
        return sReturn.substring(5,21);
    }

If the external device looses power supply. The TimerTask will be
killed. If eg. the network connection is lost, I got an exception and
the TimerTask is still running.

There shoulb be an exception as well if there is a power failure.

Thanks for any help
Mitschu