Here are two Timex digital watches that date to 1990 and 1988 using the date code that appears on back (#40 and #69). 

The Korean watch (#40) has a adjustable snap band and is overall in great cosmetic condition and the display shows the time BUT the buttons are not working properly. Removing the back, I noticed that the metal contact that acts as a spring to operate the right buttons is missing. This will need to be replaced to make the watch functional again. 

The Philippines watch (#69) has a stretch band and is also in very good cosmetic condition - and i confirmed that the contacts that operate the buttons are present and work fine if you manually connect the contact by removing the mechanism from the watch, BUT i placed the mechanism back in the body of the watch and the buttons just dont seem to push the contacts correctly and so none of the buttons work. 

I imagine if you know how to repair these kinds of watches, both are good candidates for repair and given their condition they would likely sell for over $100 each if they were functional. 

Hoping you have the skills to make these works again - unfortunately I don't have the skill or tools necessary.