New to the site/need help Poly 800

[dragonworks1]

Hello everyone. Sorry to come here with a problem right off the bat but I am between a rock and a hard place. I picked up a Poly 800 on the cheap, no sound. I was able to work up a voice from scratch and everything seems to be working correctly. Upon shutting her down, the voice I worked up was lost. So, okay, replace the internal battery backup. I open her up and I cannot find the battery. I go to a youtube video for battery replacement and find where the battery should be. Its not there. There is no battery symbol on the board like in the video. There is no evidence of a battery ever being desoldered? Okay, I download the service manual. No battery shown in the schematics or on the circuit board layout itself! No battery in the parts list so I am not even sure what battery it is supposed to take. I figured I would just check the schematic and see where to solder a battery holder in but that isn't happening. I couldn't see which traces to solder the battery holder to. They were either too fast or not close up enough for me to see.
I owned one of these back in the eighties and it was fun to play with. I know everythng is working and I don't want to junk this keyboard because I cannot find where to put the battery.
Can anyone help here?
Thanx in advance and for taking the time to read this.
J.Dragon