otari mtr-10 series

I recently acquired an Otari MTR-10 tape machine on Ebay. While it was promised in pristine condition, I am finding a lot of issues. One thing I ran into is that the power supply voltages labeled + and - 26 volts on the schematics (and also on the front panel indicator lamp) are actually coming out at + and - 22.5 volts.

I have seen these machines going for between 4-700. I was wondering if anyone had any thoughts on their reliability, sound, and a general opinion on them.



Also, if anyone has any info on the expansion card that seems to be so elusive I would appreciate it.



Thanks