Despite its historical importance, the Novachord did not enjoy commercial success. This was partly due to instability issues and the onset of World War II: reliability issues were caused in the main by the tight tolerances required of the operating parameters of hundreds of custom components. Hammond soon offered a special upgrade to improve stability, which was no more than a low-power heater bolted inside the enclosure to reduce the effects of humidity. The instrument was not known for vacuum tube failure perhaps because the heater voltage was reduced from the normal 6.3 volts to 5 volts.