The AHS 53 shown here is from the last generation of pin lever movements from Germany. It was produced around 1980 and was the base model, showing only hours and minutes.
It as got the typical diameter for those kind of movements, 10 1/2 lignes.
The base plate (hallmarked! This was pretty unusual for AHS) shows, that this movement is a very cost efficient pillar construction. There are no ruby bearings and the windig part uses a large plastic cage.
We see the typical gear train for this kind of movements: Directly driven center minute, second wheel, fourth wheel, escapement wheel. With a longer pivot, the fourth wheel could carry a decentral second hand. Here it has got the short pivot.
The speciality of this movement is the balance staff, since it doesn't use a balance cock here, but the balance wheel is beared below a bridge. This allows easier height-adjustment of the non shock protected balance wheel in its metal bearings. The anular balance beats with 18000 A/h and regulates a conventional pin lever movement.
There are no surprises on the dial side. The ratchet consists only one simple spring and we have a rocking bar winding system. At 9 o'clock you see the metal bearing of the balance wheel.
In the lab
The specimen shown here came in used but working condition into the lab and thus was only slightly oiled and adjusted.
The timegrapher results were kind of expected and are typical for a simple, used pin lever movement. There are large amplitude difference between hanging and flat positions and the differences of the rates are pretty high. The simple balance wheel bearing is probably the cause for it.
The "Domina" watch with movement in working condition is a kind donation of Günter G. Thank you very much!