diff --git a/montblanc/impl/rime/v5/CompositeRimeSolver.py b/montblanc/impl/rime/v5/CompositeRimeSolver.py
index <HASH>..<HASH> 100644
--- a/montblanc/impl/rime/v5/CompositeRimeSolver.py
+++ b/montblanc/impl/rime/v5/CompositeRimeSolver.py
@@ -249,7 +249,7 @@ class CompositeRimeSolver(MontblancNumpySolver):
             nsrc, npsrc, ngsrc, nssrc, ...
         """
         src_nr_var_counts = mbu.sources_to_nr_vars(
-            self._slvr_cfg[Options.SOURCES])
+            self.config()[Options.SOURCES])
         src_nr_vars = mbu.source_nr_vars()
 
         nsrc = self.dim_local_size(Options.NSRC)
diff --git a/montblanc/solvers/rime_solver.py b/montblanc/solvers/rime_solver.py
index <HASH>..<HASH> 100644
--- a/montblanc/solvers/rime_solver.py
+++ b/montblanc/solvers/rime_solver.py
@@ -182,6 +182,10 @@ class RIMESolver(HyperCube):
 
         return D
 
+    def config(self):
+        """ Returns the configuration dictionary for this solver """
+        return self._slvr_cfg
+
     def register_array(self, name, shape, dtype, **kwargs):
         """
         Register an array with this Solver object.
Add a config() member to RIMESolver

Returns the solver configuration dictionary