diff --git a/cumulus/src/plugins/alpha/block/configuration.py b/cumulus/src/plugins/alpha/block/configuration.py
index 5c14979a..6711f8a8 100644
--- a/cumulus/src/plugins/alpha/block/configuration.py
+++ b/cumulus/src/plugins/alpha/block/configuration.py
@@ -1398,8 +1398,8 @@ class BlockConf ( GaugeConf ):
     @property
     def coreAb ( self ):
         if not hasattr(self,'coreSize'): return Box()
-        #trace( 550, '\tcoreAb:[{} {}]\n'.format( DbU.getValueString(self.coreSize[0])
-        #                                       , DbU.getValueString(self.coreSize[1]) ))
+        trace( 550, '\tcoreAb:[{} {}]\n'.format( DbU.getValueString(self.coreSize[0])
+                                               , DbU.getValueString(self.coreSize[1]) ))
         return Box( 0, 0, self.coreSize[0], self.coreSize[1] )
 
     @property
diff --git a/cumulus/src/plugins/alpha/chip/__init__.py b/cumulus/src/plugins/alpha/chip/__init__.py
index 69782229..adc1cd23 100644
--- a/cumulus/src/plugins/alpha/chip/__init__.py
+++ b/cumulus/src/plugins/alpha/chip/__init__.py
@@ -141,8 +141,12 @@ class CoreWire ( object ):
         trace( 550, '\tbbSegment: {}\n'.format(self.bbSegment) )
         self.symSegmentLayer = None
         for layerGauge in rg.getLayerGauges():
+            trace( 550, '\tTrying: {}\n'.format(layerGauge) )
+            if layerGauge.getType() == RoutingLayerGauge.Unusable: continue
+            if layerGauge.getType() == RoutingLayerGauge.BottomPowerSupply: continue
             if layerGauge.getDepth() > self.conf.topLayerDepth: break
             if layerGauge.getLayer().getMask() == mask:
+                trace( 550, '\tUsing: {}\n'.format(layerGauge) )
                 self.symSegmentLayer = layerGauge.getLayer()
                 if self.preferredDir:
                     self.symContactLayer = self.symSegmentLayer
@@ -155,11 +159,15 @@ class CoreWire ( object ):
                                        , DbU.getValueString(self.symContactSize[1]) ))
                 else:
                     depth = layerGauge.getDepth()
+                    trace( 550, '\tChoosing PP layer, {}+1 > top={}\n' \
+                                .format(layerGauge.getDepth(),self.conf.topLayerDepth) )
                     if layerGauge.getDepth() + 1 > self.conf.topLayerDepth:
                         self.symSegmentLayer = rg.getLayerGauge( depth-1 ).getLayer()
                         depth -= 1
+                        trace( 550, '\tUsing below layer {}\n'.format( self.symSegmentLayer ))
                     else:
                         self.symSegmentLayer = rg.getLayerGauge( depth+1 ).getLayer()
+                        trace( 550, '\tUsing above layer {}\n'.format( self.symSegmentLayer ))
                     self.symContactLayer = rg.getContactLayer( depth )
                     if self.side & (West|East):
                         self.symContactSize  = ( self.bbSegment.getHeight(), self.bbSegment.getHeight() )
diff --git a/cumulus/src/plugins/alpha/chip/chip.py b/cumulus/src/plugins/alpha/chip/chip.py
index d1df6fe3..dc1b2bc6 100644
--- a/cumulus/src/plugins/alpha/chip/chip.py
+++ b/cumulus/src/plugins/alpha/chip/chip.py
@@ -94,6 +94,8 @@ class Chip ( Block ):
             self.validate()
             minHCorona = self.conf.minHCorona
             minVCorona = self.conf.minVCorona
+            trace( 550, '\tminHCorona={}\n'.format(DbU.getValueString( minHCorona )))
+            trace( 550, '\tminVCorona={}\n'.format(DbU.getValueString( minVCorona )))
         else:
             self.padsCorona = plugins.alpha.harness.pads.Corona( self )
             self.padsCorona.doLayout()
diff --git a/cumulus/src/plugins/alpha/chip/configuration.py b/cumulus/src/plugins/alpha/chip/configuration.py
index 6f4f2536..ab6cdffd 100644
--- a/cumulus/src/plugins/alpha/chip/configuration.py
+++ b/cumulus/src/plugins/alpha/chip/configuration.py
@@ -153,13 +153,15 @@ class ChipConf ( BlockConf ):
             self.railsCount = self.cfg.chip.block.rails.count + len(clockNets)
         trace( 550, '\tself.railsCount: {}\n'.format(self.railsCount) )
         hRailsSize = self.railsCount*(self.hRailWidth + self.hRailSpace) + self.hRailSpace
+        trace( 550, '\thRailsSize={}\n'.format(DbU.getValueString( hRailsSize )))
         if hRailsSize % self.sliceHeight:
             hRailsSize += self.sliceHeight - (hRailsSize % self.sliceHeight)
-        self.minHCorona = hRailsSize + self.sliceHeight
+        trace( 550, '\thRailsSize (sliceHeight)={}\n'.format(DbU.getValueString( hRailsSize )))
+        self.minHCorona = hRailsSize #+ self.sliceHeight
         vRailsSize = self.railsCount*(self.vRailWidth + self.vRailSpace) + self.vRailSpace
         if vRailsSize % self.sliceHeight:
             vRailsSize += self.sliceHeight - (vRailsSize % self.sliceHeight)
-        self.minVCorona = vRailsSize + self.sliceHeight
+        self.minVCorona = vRailsSize #+ self.sliceHeight
 
     def chipValidate ( self ):
         #self.checkPads()
diff --git a/cumulus/src/plugins/alpha/chip/pads.py b/cumulus/src/plugins/alpha/chip/pads.py
index 455d2d0e..50fd9eff 100644
--- a/cumulus/src/plugins/alpha/chip/pads.py
+++ b/cumulus/src/plugins/alpha/chip/pads.py
@@ -774,6 +774,7 @@ class Corona ( object ):
         self.northSide.gap = self.southSide.gap
         self.eastSide.gap  = self.southSide.gap
         self.westSide.gap  = self.southSide.gap
+        trace( 550, '\tMinimum gap: {}\n'.format(DbU.getValueString( self.southSide.gap )))
         for coronaPlug in self.conf.icorona.getPlugs():
             chipIntNet = coronaPlug.getNet()
             if not chipIntNet:
@@ -802,6 +803,10 @@ class Corona ( object ):
                     raise ErrorMessage( 1, 'PadsCorona._placeInnerCorona(): Chip net "{}" is not connected to a pad.' \
                                            .format(chipIntNet.getName()) )
         self.conf.setupCorona( self.westSide.gap, self.southSide.gap, self.eastSide.gap, self.northSide.gap )
+        trace( 550, '\tWest  side gap: {}\n'.format(DbU.getValueString( self.westSide.gap )))
+        trace( 550, '\tEast  side gap: {}\n'.format(DbU.getValueString( self.eastSide.gap )))
+        trace( 550, '\tSouth side gap: {}\n'.format(DbU.getValueString( self.southSide.gap )))
+        trace( 550, '\tNorth side gap: {}\n'.format(DbU.getValueString( self.northSide.gap )))
         self.coreSymBb = self.conf.getInstanceAb( self.conf.icorona )
         self.coreSymBb.inflate( self.conf.toSymbolic( self.westSide.gap //2, Superior )
                               , self.conf.toSymbolic( self.southSide.gap//2, Superior )