Author Topic: Service: Romanoff Chronograph, Poljot cal.3133  (Read 3095 times)

kanikune

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Service: Romanoff Chronograph, Poljot cal.3133
« on: March 12, 2015, 09:26:53 PM »
Poljot chronograph is getting serviced.



Even though the case design let's you think the straps are attached by screws, there's normal spring bars inside. Luckily I didn't unscrew these!


Mainspring can be released from a tiny hole under the hammer.


Simple view, as everything is hidden below bridge. Planet wheel drives the date wheel.


Date wheel click is held in by a method more commonly used in clocks :)


Keyless works is more traditional. The date wheel's center part is actually solid and part of the mainplate.


Chronograph mechanism takes the power directly from the 4th wheel. In the picture there's three chronograph wheels in a row. The left one is directly attached 4th wheel pivot. When timing is activated a wheel (above the aforementioned) moves to connect driver from chronograph runner wheel and chronograph seconds wheel. The most right of the wheels is minute recorder.


First the springs are removed from the chronograph mechanism.


Hammer removed. This resets the timing wheels.


Brake removed. This holds the chronograph second hand steady while the timing is in stop state.


Chronograpgh bridge removed. Below are the heart-shaped surfaces. Hammer struct to these in reset. This will force the wheels to rotate to zero position from any position they were before.


Chrono seconds wheel is supported from the below with spring slip. I guess this implementation is to lower total height of the movement.


Small bridge for the chronograph settings. Click is starting be  visible.


This spring helps to return pushers. The actual pushers might have their own return springs, but the mechanism also requires "movement pushers" to return to zero position.


Chrono driving wheel still attached to 4th wheel.


From this point forward normal manual wind watch service, until chrono assembly. The shock spring is incabloc-styled from the business end, but there is "hinge" on the other end. The other end just slips in.


Ready for cleaning.


Clean start. There's no jewel for the 3rd wheel..


There's separate cock for it. In Valjoux 7734, which this movement is copied from, does not hava this bridge. Poljot structure is better, as wheel does not need to be bent to get it out.


Going train.


Bridges return.


Cannon pinion assembled. Shock settings happily back in place.


Keyless works.


Also this Poljot has balance wheel end shake adjusted by shim disks. Initially I was confused as the balance wheel was touching the 2nd wheel after assembly, but then I noticed that shock setting was not straight, causing balance to be tilted.


Back in proper function.


Chronograph being assembled.


Next to put back the chronograph springs. Luckily most of the chrono springs are secured with screws.


In the lower right corner of the movement, the brass colored spring snaps the minute wheel to point to a next index in dial.


The planet wheel revolves several times per day, but only touches date wheel once!


Rate and amplitude ended up setting nicely.


New crocodile strap to compliment the classic style of the watch.

Jameahan

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Re: Service: Romanoff Chronograph, Poljot cal.3133
« Reply #1 on: September 25, 2018, 06:33:28 AM »
The feeling of me now is very glad to be with everyone here.