There is a bug report here that describes accurately what I am experiencing; perhaps the cause of the problem and the fix apply as well. https://github.com/FTBTeam/FTB-Revelation-2/issues/242 I have created a mob spawner using the RFTools mod's Spawner and three Matter Beamers; the beamers send a beam of energy to the Spawner, converting objects like Leather and Dirt to energy. All mobs require at least one beamer dedicated to creating Living Matter energy, converting stuff like raw meat or wheat. No matter how I switch beamers around, the beamer responsible for Living Matter never works; it does not up the Living Matter number on the Spawner and thus no mob will every spawn. RF energy, redstone signals, source material feed, I have it all sorted out and checked numerous times. The Living Matter beamer refuses to work.