Hi. Do you have a photo of the watch? The most likely movement in the watch is a ESA 556.111, which is basically the same as the ETA 956.111. This quartz movement was commonly used by TAG Heuer in the 1980s for the lady range.

If that is correct, then the movements are quite cheap to buy. For example, here is one in another NOS watch on sale for $25:

http://www.ebay.com/itm/Prisma-flat...724141754?pt=Wristwatches&hash=item3f44055cbaPurchases made through these links may earn this site a commission from the eBay Partner Network

This won't have the correct TAG Heuer markings, but this is purely cosmetic.

Best bet would be to have it looked at by a watchmaker, who can also confirm the movement- but remember that you will be able to buy a new movement for less than it will likely cost to repair.

dc

 

Here is the watch in the 1987 Catalogue:


I doubt that you are doing anything wrong- typically pulling the crown out all the way will change the time and the position before that will change the date.

My guess is something is stuck with the date wheel given the rest of the watch is working.

dc