Bogdan swapped the high voltage cables between the top and bottom chambers. The inefficiency was found to follow the swap. Jessie and I took an iron-55 source up and checked the gain with a Fermilab E711 preamplifier. The gain on one of the chambers was about half of the gain in the other chamber. The check was to have the setup to check the gain with the spare power supply. We installed the spare Bertan high voltage power supply and the gains of the two VDCs are about the same as what the top VDC seems to have been running at (based on the gain we saw on the bottom VDC after the cable swap).