Ronda 4139

 
Ronda 4139 |

Ronda 4139

Description

This Ronda “Ronda-Matic” selfwindig movement, caliber 4139, was made in the warly 1980ies. It was part of the caliber family 413x/423x/433x/443x, which was produced in different sizes, ranging from 8 3/4 up to 12 lignes, and was available as handwind and selfwindig versions. The calibet 4139 winds in one direction and uses a swiss lever movement, although it is signed as “RL”, which normally stands for Ronda pin-lever movements.

It offers all possible kinds of indications, hour, minute, second, date and weekday (in names as well as in digits from 1 to 7). The date can be quickset by a very unique mechanism: When you set the time backwards, the date advances every 30 minutes.

A big thanks to Mr. Stahl from the Ermano Uhrenwerke GmbH for identifying this movement and providing me very interesting details about it.

Technical data

Manufacturer:Ronda
Caliber:4139
Size:8 3/4'''
A/h:21600
lift angle:52°
Number of jewels:21
Escapement:Pallet lever
Balance types:Nickel anular balance
Shock protection(s):?
Balance bearing / direction hairspring:Counterclockwise
Moveable stud:yes
Adjust mechanism:Hairspring key
Features:
  • SC? (center seconds (type unknown))
  • QG (date indication (aperture))
  • JG (weekday indication (aperture))
  • RDR (date corrector)
  • AUT (selfwinding)
Production period:198x
Datasheet:calibers 4131-3349
Hint: The jewel count, the types of balances used, and the shock protections employed refer only to the specimens held in the archive and are therefore not relevant for the precise identification of the movement.

Usage gallery

Ronda 4139: Pomar Automatic ladies' watch

Pomar Automatic ladies' watch