Just to be sure we're seeing the same thing: "Mudd's Women" Four fist-sized lithium crystals (only addressed as "lithium" crystals). Seen and in dialogue. single Converter Assembly. Spoken of but not seen. "The Alternative Factor" Four paddle dilithium crystals. Seen and in dialogue. Four paddles in an "energizer". Spoken of and seen. Four paddles being "re-amplified". Spoken of but where and when were they re-amplified? Question - if they were re-amplified when the first two were stolen, why again were they still at the energizer when the last four were stolen when they a) did not need to be re-amplified and b) Kirk is counting on these last two for power, even if it is not full power? Converter Assembly. Not spoken of. Unknown if seen. "Elaan of Troyius" Dilithium crystals. Spoken of but not totals and one seen. Fused Converter assembly. Spoken of. However, we only see one blackened crystal in the holder. Question - is the converter assembly below and unseen and as Timo said the holder is just on some sort of mini-elevator to somewhere deep in the ship? We know that they fit the new crystals to the same holder, so obviously that is not the fused converter assembly since the holder still worked... What I'm trying to point out is that there are three different versions of the power system here probably from 3 different upgrades (in-universe). Still, there are some things in common: Four Lithium/Dilithium crystals (first two example episodes) Multiple crystals (last) Single Converter Assembly (first and last) EDIT: Regarding "re-amplification": In the context of this episode, it is specifically to "undrain" (I know it isn't a real word ) the drained crystals. In other words, Kirk wanted the crystal power back to full power and that meant adding power back into the crystals. MASTERS: Whatever that phenomenon was, it drained almost all of our crystals completely. It could mean trouble. KIRK: You have a talent for understatement, Lieutenant. Without full crystal power, our orbit will begin to decay in ten hours. Re-amplify immediately.