i did solder in the battery holder, and also took apart all the buttons to clean them. it works.. but i think i might have fried something connected to the negative terminal when soldering in the wires for the battery. which would be the dumbest thing i've done in a while.
the sound output is real quiet and some patches are inaudible. not sure where to start troubleshooting, or if there's another explanation. i was thinking a master trimpot of some sort but i didn't adjust anything, frying seems like the best explanation i was pretty casual with the soldering iron and the negative leg was taking some time to join. never burned out anything soldering before so wasn't really thinking about it.