diff -u -r1.2 -r1.3
--- TrackHelixPlusHitExtrapolator.java	23 Sep 2008 18:24:59 -0000	1.2
+++ TrackHelixPlusHitExtrapolator.java	23 Sep 2008 18:26:03 -0000	1.3
@@ -104,7 +104,16 @@

 		m_intercept = m_swimmer.getPointAtDistance(m_alphaIntercept);
 		m_barrelValid = validBarrel;
 		m_endcapValid = validEndcap;

-		if (m_debug) { System.out.println("DEBUG: "+this.getClass().getName()+" extrapolated OK."); }

+		if (m_debug) { 
+		    System.out.print("DEBUG: "+this.getClass().getName()+" extrapolated OK. validEndcap="+validEndcap+" and validBarrel="+validBarrel+" and m_alphaIntercept="+m_alphaIntercept); 
+		    if (m_intercept == null) {
+			System.out.print(" -- but intercept point is null!");
+		    } else {
+			double r = Math.sqrt(m_intercept.x()*m_intercept.x() + m_intercept.y()*m_intercept.y());
+			System.out.print(" -- intercept point at r="+r+", z="+m_intercept.z());
+		    }
+		    System.out.println();
+		}

 		// Output
 		HelixExtrapolationResult output = new HelixExtrapolationResult(new TrackHelixPlusHitExtrapolator(this));
 		return output;

diff -u -r1.3 -r1.4
--- TrackHelixExtrapolator.java	9 Sep 2008 22:32:06 -0000	1.3
+++ TrackHelixExtrapolator.java	23 Sep 2008 18:26:03 -0000	1.4
@@ -86,9 +86,11 @@

 	// Did we make a successful extrapolation?
         if ( Double.isNaN(m_alphaIntercept)) {
 	    // No -- extrapolation failed

+	    if (m_debug) { System.out.println("DEBUG: "+this.getClass().getName()+" failed to extrapolate: alpha is NaN"); }

 	    return null;
 	} else if ( !(validEndcap || validBarrel) ) {
 	    // Invalid state

+	    if (m_debug) { System.out.println("DEBUG: "+this.getClass().getName()+" failed to extrapolate: not a valid barrel or endcap point"); }

 	    return null;
 	} else {
 	    // One or both solutions valid.

@@ -106,10 +108,23 @@

 		    validBarrel = tightValidBarrel;
 		}
 	    }

+

 	    // Extrapolation succeeded.
 	    m_intercept = m_swimmer.getPointAtDistance(m_alphaIntercept);
 	    m_barrelValid = validBarrel;
 	    m_endcapValid = validEndcap;

+
+	    if (m_debug) { 
+		System.out.print("DEBUG: "+this.getClass().getName()+" extrapolated OK. validEndcap="+validEndcap+" and validBarrel="+validBarrel+" and m_alphaIntercept="+m_alphaIntercept);
+		if (m_intercept == null) {
+		    System.out.print(" -- but intercept point is null!");
+		} else {
+		    double r = Math.sqrt(m_intercept.x()*m_intercept.x() + m_intercept.y()*m_intercept.y());
+		    System.out.print(" -- intercept point at r="+r+", z="+m_intercept.z());
+		}
+		System.out.println();
+	    }
+

 	    // Output
 	    HelixExtrapolationResult output = new HelixExtrapolationResult(new TrackHelixExtrapolator(this));
 	    return output;

diff -u -r1.3 -r1.4
--- HelixExtrapolator.java	9 Sep 2008 22:31:49 -0000	1.3
+++ HelixExtrapolator.java	23 Sep 2008 18:26:03 -0000	1.4
@@ -92,6 +92,10 @@

 	m_debug = old.m_debug;
     }
 

+    public void setDebug(boolean debug) {
+	m_debug = debug;
+    }
+

     /** Allow use of FCAL. */
     public void useFCAL(boolean use) {
 	m_useFCAL = use;