Jeff,
The Ref is 0634-5019. I bought this watch in 1975 as it was the first LCD Chronograph I had seen.
I was shamefully seduced by the digital read out in tenths of a second, so it replaced the Rolex 6238 I
had been wearing daily since 1968. It cost USD 300 which made it about 50% more expensive than it's
mechanical predecessor. In 1977 I spotted a later Seiko development that read in hundredths of a second
and had an alarm. So I sinned again.

The two Seiko electric watches are my only contribution to the mechanical watch debacle of the 1970s.
I accept my poor judgement in helping to cause the decline and promise never to do it again
By 1980 I came to my senses and bought a Heuer Pasadena from The Timing Stand for USD 300.
I wore this watch daily untill I got the serious watch collecting bug around year 2001.

A few years ago I thought I would have the 1975 seiko factory refurbished as the crystal was
scratched and the buttons worked poorly. They had no replacement parts and the LCD was ruined by
the disassembly so I turned it into an aquarium like an old Macintosh compact computer.

This story lends credibility to the following quote I saw on a forum once.

author unknown
Even if a steel part for an old watch is no longer available, a watch restorer could make one.

With the advances of semiconductor technology the production lines for the old parts are torn up and thrown away.
Even if you had the design information of those old ICs there are no production lines available to make them any more.
Of course it is theoretically possible to make them again, but the investment needed is many, many, many orders of
magnitude more than you need to make a steel or brass part.

Electronics is throw away technology, even at the low temperatures of watch ICs the doping will wander with time.
At some point one of the transistors will stop working and.. there you have it.
In 100 years our mechanical watches will all be still working or at least serviceable.
Maybe you will replace the springs with newer steel, but they will work.
The quartz watches all will be comfortably filling a waste heap somewhere.

Some illustrations:

Old soldiers never die!

The 1977 Seiko is still running but never worn.

The Little old lady from Pasadena ..........

And finally the USD 219.30 Rolex.