The TH-215 is now working. Thanks to Clif (KA5IPF) and Aaron (N2HTL) for their kind assistance. I managed to get the IF board out and when I turned it over there was gunk on a transistor lead near C38. I suspected a leaking capacitor so removed both C37 and C38. I replaced them with 16V units and now have full volume. 73, Don VE3HUR