Frank as said replace the Motherboard battery. Plug in motors etc....boot, it'll come up CMOS reset...that ok just lost all SRAM data
Enter data as per manual, mount type, time zone offset lat/long (minus for latitude is south), UTC using gemini format,
Gemini UTC display (yymm.dd: hh.mm.ss).
I generally set slew and got speeds at 500-600 to lower noise and less motor strain.
As for the mount...yeah its been sitting a bit you might want to see how the axes feel rotating by hand clutches undone......and obviously all the grease is not very lumpy. Yes you can clean re-grease the bearings....it'll probably need it buy now. But essentially it should work but might be a bit "gummy" on worms & bearings and clutch pads may need clean up etc
Of course the
Gemini FAQs may help rekindle the mind.
cheers, good luck
Bren