Well, Lets try it my way. Fight monsters and summon the aeons, when their overdrive full, dismiss them. Do that to every of your aeons. Before the battle, make sure ALL your aeons are on overdrive. And i reckon your characters too. That machine has 60k health??or something like that, at this stage, your aeon's overdrive should do around 9999 damage without the celestial weapons. If not, TRAIN YOU ARE WEAK!!!. Get your Wakka to blast the flying negator. Dead, use Yuna and summon ur overdrived aeons AND BLAST that machine. And by the way, while you are using your aeons, it sometimes have another negator out, but don't worry, your aeon's overdrive can hit all enemies. BECAREFUL OF THE MANA BEAM, THATS THE ONLY REASON YOU DIE EVERYTIME. The machine will never be able to kill you without that stupid mana beam. After each mana beam be sure to change low health characters to hgih health ones. And the aeons speed, Valefor and Shiva are the fastest aeons, if lucky enough to survive 1 or 2 hits from the machine after you used the aeon's overdrive, you will get another full overdrive bar. Oh yeah i'm sorry you hav'nt got Shiva yet, but you will later. That means..... Valefor Ifrit and Ixion. Ixion's attack deals the most to the machine. Once all your aeons are dead, the machine should'nt have much health left, use your strongest characters to defeat it. After Mana beam, try use mega potion. Oh and by the way, HASTE. Hope this helps ^_^.