A somewhat beat up Gruen wristwatch came my way, and I would appriciate some help with it. From the looks of it I'd estimate that its from the 70's (based on the case design), but I have been unable to verify much about it.
The watch has a day/date funtion, with the day "number" in front of the day (for some reason). The case is "golden" finish, but I have no idea about the actual type of finish. The caseback is stainless steel. The dial is silver, with raised gold numerals. The dial reads " Gruen Precision", "Automatic Incabloc".
The outside of the caseback reads "Stainless steel back, Water resistant, Anti Magnetic, Swiss Incabloc, Automatic". On the inside of the caseback a faint inscription seems to read "NK 10/IX 75" (possible manufactor date?). The rotor reads " Gruen 03, 25 jewels Swiss Made", and I *think* I can read a "ETA" logo and the an inscription saying "HX 2789". Would this make it a ETA 2789 movement?
Finally I find that the watch will run while on my arm, but even after a full day of wearing it, it will "run down" after a couple of hours. I find the crown very hard to turn (as in winding it). Should it be possible to hand wind this watch?
I appriciate all and any info on this watch!