Seiko’s flagship watch of the early 1980s was the G757, but a very close second — and one that shares a lot of similarities right down to the circuitboard design — was the D138 ‘Running Man’.
Unfortunately the similarities don’t end with the look and feel of the watch, it also has an equally finicky circuitboard and LCD, either of which can stop working for seemingly no good reason.
Because of this, finding a fully-working D138 is a rare thing. Like the G757 it draws a lot of power from the single SR1120SW battery (take a look at the animated dot matrix screen and you’ll see why) and now it’s nearly 40 years old, the capacitors are no longer really up to the task.
The LCD is complicated, too, so has often degraded so segments, dots etc are missing and parts are pretty much non-existant for this now.
This one came about after I found a NOS circuitboard for sale and bought it to test another collector’s watch to see if it was the cause of it non-working (unfortunately it was his LCD that was at fault, so wasn’t able to fix it). So, the circuitboard just sat in my spares until the watch you see in the picture appeared on eBay for sale from India.
It arrived absolutely filthy (which I expected so no problem there — pretty much anything can be washed off if you’re patient) but the buttons were rusted in as well, and had to be removed with side cutter pliers, even after liberal costings of penetrating oil to no avail.
Fortunately I had a G757-5030 case in bad condition but with working buttons so was able to transfer these, although they didn’t have pusher gaskets, hence why the buttons stick out a bit further than they should.
The module was also rusted beyond repair, but — amazingly — the LCD worked, so paired this with my circuitboard in an old G757 module holder, and bingo!
While the G757 and D138 modules are almost identical, they aren’t exact, so a little but of fine filing was required to make it fit perfectly.
The last thing I (stupidly) did was to remove the front glass so I could clean the insert. Disaster. The glass shattered upon removal and the insert was bent.
It almost went back into the spares bin, but the junk G757-5030 came to the rescue again (they have the same crystal) and some sanding and polishing later, it’s intact.
Not perfect, but there are enough non-working D138s around that I could get a better case if it ever comes to that. I do like the well-worn look, though, as unintentional as it is, so will probably leave it as-is for now.