diff --git a/CosmicPiV2I2CSPItest.ino b/CosmicPiV2I2CSPItest.ino
index 0aeb094..f684610 100644
--- a/CosmicPiV2I2CSPItest.ino
+++ b/CosmicPiV2I2CSPItest.ino
@@ -130,6 +130,10 @@ void loop() {
        }
     case 5:
       {
+        Serial.println("disabling HV");
+        spi_exchange(11);
+        spi_exchange(0);
+        
         Serial.println("enabling HV");
         spi_exchange(11);
         spi_exchange(3);