before ya crack it open do you have a Multi meter? check the center lead(2mm bullet) for the balance tap from the bullet to the balance plug and make sure its not "open"... I have several of these packs and more than one had COLD SOLDER joints either at the bullet or fake deans... the joints at the fake deans i found quick as i replace them outa the box... the cold joints at the bullets caused me a few short runs before i just went through and resoldered ALL the leads. outa the 6 packs i have i haven't needed to open one yet for a bad connection... all the bad connections were on the leads