The mid-seventies movement EB 8503, here in the 1976 version, is a very
idiosyncratic pin lever movement, which was constructed completely
due to rational and cost-efficient production.
Although it is visually not much inspiring and due to its one-way construction with
riveted plates it reminds strongly of a alink href="../../t/timex/index.php">Timex
movement, there are noteable differences to these movements. But one similarity
share both - the movements are disposable and cannot be repaired on errors. And the
EB 8503 came up just at the time, when Timex watches were most popular in Europe and
could be found even in supermarkets and hence on almost every wrist.
The bridges of the EB 8503-76 are made of die-cutted metal sheets (a method
which was even patended), but at least they contain ruby bearings for all gears.
The crown wheel has got a special kind of bearing: It is mounted loosely, so that it
drives the mainspring barrel in one direction and in the other direction, it just
slips away and turns freely. A simple but efficient construction.
The regulation works with its massive (means here "not open worked") gears is
constructed in a conventional way: A very flat ring balance, which is even beared
in two Novodiac shock protections, beats with 21600 A/h. Its hairspring is fix
soldered(!) to the balance bridge and can be regulated in its effective length
with a simple u-shaped wire, which works as hairspring key. The escapement system
is a pin lever. It controls a movement with directly driven center second
and an indirectly driven minute hand on the dial side - a modern
construction.
One of the special constructions of this movement is the winding system: Unlike
on normal movements, there's no yoke winding system and no rocking bar system, too, but
the crown wheel is plugged into a connector wheel, which either drives the
dial setting wheel (when pulled out) or the winding wheel (when pushed in). In the
video, you can see this minimalistic construction working.
dial side view
The date setting mechanism is invisible, since the top plate is riveted and
cannot be removed. The driving mechanism for the minute wheel is invisible, too.
Technical data
Manufacturer
EB
Caliber
8503-76
Number of jewels
17
Escapement
pin lever
Balance
Nickel
Shock protection(s)
Novodiac
Balance cock direction
centered (bridge)
Hairspring stud
fixed
Regulator type
Hairspring key
Movement construction
Fork Escapement wheel, Fourth wheel, Third wheel, Large driving wheel, Mainspring barrel
Construction type
pillar construction
Bridge shape
Arrow, modern type, 3 gears
Winding mechanism
unusual type
Features
SCD,QG
Functions
Hour, minute, second, day
Beats per hour
21600
Size
111/2''' (measured: 26,4 mm)
Production time
1976 - ?
Factsheet
Test Results
The specimen shown here looked brand new, but was completely
resinified. Since it could not be taken apart, it has to be cleaned as
a whole, which caused the printing of the date wheel to disintegrate.
The movement worked at first pretty well, after it was cleaned and olied,
but after a few days, it stopped working again.
Timegrapher Protocol
As expected, the timegrapher printings show very consistent lines, which prove
the minimal wear of this movement. Especially the very small beat error shows, how
effective the robots, which made this movement, worked.
In sum, the deviations were pretty high, but with a median regulation, this
movement could have been regulated in a way, that it would show only minimal
deviations when worn. For a movement of the lowest class, a pretty good result.
