Here are two videos on how to maintain your Delta-T. Due to my association with Dr. Gohl, I’ve spoken to Dr. Ed Carr on quite a few occasions. He taught me how to fix most issues with the Delta-T. The easiest fix is change the battery every THREE months to avoid weird readings. All the other fixes are shown in these videos, including how to drill out the Delta-T to fix the arms. Reach out to Dr. Carr at The Instrument Company.