:
:
: This movement is in all early mens size Heuer diver, both 38mm and
: 42mm.

: After some time the "L" version appeared. All
: "L" Heuer/Tag Heuer divers I have seen/handled have a
: different ESA early quartz movment. It's easy to spot with it's
: battery placed upside down. These "L" watches is easy
: to date. The year is printed on the movement. I can find the ESA
: number for this movement later today. I have to open a watch to
: look.

:
:
: Movement in a "L" diver. This movement is a little lower
: than the first ESA 536.121 so the case had to be a little
: modified. Dated from 1985.

: Finally in the "N" the movement is the ETA 955.114. This
: is a musch slimmer movement so the case is modified again. The
: case back is often lower than in the earlier watches.

:
:
: ETA 955.114 as in all "N" divers. Easy to date, this one
: has 90 (1990) stamped on the movement.

: This is what I have concluded after I have studied a lot of
: pictures and handled some of these watches. I might be wrong but
: I think this is the answer.

: If you could open your 980.023L and see if it has the movement
: shown in the middle, with the upside down battery, we have a
: conclusion.

: Regards
: Jarl
: www.classicheuers.blogspot.com