Kurzweil K2000RS #2 Problematic

This unit does not always functioning properly. OS is 2.08j. The back light in this unit is the dimmest of all three units we are currently testing. It can still be read in the dark but it’s not so bright. The last line of the rom test showed some strange characters but did not say fail. The other three lines passed. After this unit was on for a few hours and working fine, I powered off and on and the welcome screen shows the operating system number but then it says “waiting for key scanner” and the screen goes blank. The next morning the unit worked fine, so this issue is intermittent. Our tech can fix just about anything, but we haven't had him look at it as we need him to work on much more valuable items. We are selling this unit as is, hopefully repair, but if not, for parts. This unit contains the pram board. It looks like there was some liquid inside the base of the left side of the unit at some point as there’s white residue on the bottom of the chassis (see pics). There doesn’t appear to be any on the tops of the circuit boards. There’s lots of dust there though. Ram test suggests there's 8m of ram. Volume knob jiggles just slightly and pot has slight crackle. 

We are selling another unit that’s in much better shape. Please search our listings if interested.