Date Wheel movement

[chrisdt]

Hope everyone is well and not suffering too much eye strain. On the ETA 2783 -1....Could someone please explain the correct function of the date drive wheel or at least one of its components, the small copper coloured pin which emerges from the centre hub, gets ready to turn the date wheel, fails to do so then disappears behind the hub until the cycle has passed. Is the reason it fails to turn the date wheel because the spring is weak or date wheel too tight in its location or some other reason?  The pic is a Garrard S76/28 which I think is very similar.

Edited June 10, 2020 by chrisdt
error

[Nucejoe]

Date jumper appears tucked under the date disc in the picture. it should engage level with the teeth. 

Refer to your pic ,between at 12 and 13th day.

[chrisdt]

That is because I loosened the plate at 14 to see if it was binding. The date wheel revolves easily by the 'Quickset' method but will not move by moving the hands or by normal working of the watch

[HSL]

Well lets try to explain the function... There use to be three positions on the setting lever.
1. Winding
2. Date setting 
3. Time setting

In position 2 the setting lever pushes (the date corrector lever) the setting wheel onto the date corrector.
The date corrector has three paddles that will turn the date ring in one direction.
Due to it's design you cant switch the date backwards.

In position 3 the setting wheel will engage the minute wheel . The minute wheel drives the Hour wheel.
The hour wheel drives the intemediate date wheel, this is held in place by the date indicator guard . On the date indicator driving wheel there should be a smaller wheel which drives the date indicator driving wheel. the intermediate wheel must turn free in the guard .

On the date indicator driving wheel there should be a spring loaded pin which allows for date shift in one direction (clockwise) but not in the other. Sometimes this springloaded pin is to worn or dirty so it will not grabb onto the date ring.

The date jumper will ensure you get a snappy dateswitch and later on keep the ring in position.

The dial is held in place by the date indicator guard and the minute work cock. These two must be exactly flat or the datering will not move.

So in this picture the date indicator guard looks beaten up and as previously said the date jumper is out of position.

 

Edited June 10, 2020 by HSL
Swinglish

[oldhippy]

I expect the calendar has worn. You will need to replace it with a  new one. 

[chrisdt]

Thanks HSL for your very detailed and instuctive reply. I appreciate the date jumper is out of position in the pic but when in position and the hands turned the date driving wheel engages with the teeth of the date wheel then takes the least line of resistance and is pushed in by the teeth towards the hub without moving the wheel at all. Thanks OH I will try it with a new one.