vintage Nivada crono wrist watch dissasebly

[vinn3]

  can i let down the main spring without removing the movement from the case?

[AndyHull]

Perhaps...

Post a few pictures, and we can advise.

Edited August 26, 2019 by AndyHull

[Nucejoe]

Caliber please, pix help.

Regards joe

[vinn3]

2 hours ago, Nucejoe said:

Caliber please, pix help.

Regards joe

   best i can do is describe;  outer case number 85051 - inner,  5750.  can't upload from hard drive.  don't trust storage like " the bucket".   vin

[vinn3]

2 hours ago, Nucejoe said:

Caliber please, pix help.

Regards joe

  don't know how to calulate Calibre,  but i can measure the case dia. and describe:  2 knurled and 2 pushers.  vin

[vinn3]

   i finally found something that looks like mine "on the net".  Nivada GMT crono.     ill take the mvt. out to look for numbers.   vin

[Nucejoe]

Nivada chrono GMT,s are rare and expensive pieces. Be careful with it.

Perhaps should get all set up for pix and read up on them. Get data sheet.

[vinn3]

    i looked a little closer - on  the mvt.,  - 17 jewels,   724 _ _ _ near the balance bridge.  all the screw heads apear un touched except scratches on the balance bridge and the mvt. holding clip screw is a little buggered.   it is possable someone took the balance out to let down the main spring.    i am still searching the net for a "data sheet".    vin

[stevew]

Just drag and drop pictures into a post. No need for photobucket etc

[vinn3]

9 minutes ago, stevew said:

Just drag and drop pictures into a post. No need for photobucket etc

   thanks, ill give it a try.

[vinn3]

7 hours ago, vinn3 said:

    i looked a little closer - on  the mvt.,  - 17 jewels,   724 _ _ _ near the balance bridge.  all the screw heads apear un touched except scratches on the balance bridge and the mvt. holding clip screw is a little buggered.   it is possable someone took the balance out to let down the main spring.    i am still searching the net for a "data sheet".    vin

   another posibility;  they may have taken the balance out just to find those numbers and missed the pallet fork,  hence, why the main spring is wound up tight.  vin

[vinn3]

    Nivada pic,s  from blackberry -

[vinn3]

15 hours ago, vinn3 said:

   another posibility;  they may have taken the balance out just to find those numbers and missed the pallet fork,  hence, why the main spring is wound up tight.  vin

     sorry about the poor pic's.   dia.   39.5 MM. vin

Edited August 28, 2019 by vinn3

[AndyHull]

Looks like a Valjoux 72 or derivative, something like this -> http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Valjoux_72

This may be sufficiently similar to be of use.

 

 

Specifically this PDF may assist with letting down the mainspring if the two calibers are sufficiently similar.

https://www.strela-watch.de/wp-content/uploads/2013/12/Valjoux-7733-7734-7736-technical-communication-service-manual-EBAUCHES-SA.pdf

 

Edited August 28, 2019 by AndyHull

[Nucejoe]

I say landeron and rare caliber of.

[nickelsilver]

It's definitely a 72.

[vinn3]

On ‎8‎/‎28‎/‎2019 at 6:18 AM, AndyHull said:

Looks like a Valjoux 72 or derivative, something like this -> http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Valjoux_72

This may be sufficiently similar to be of use.

 

 

Specifically this PDF may assist with letting down the mainspring if the two calibers are sufficiently similar.

https://www.strela-watch.de/wp-content/uploads/2013/12/Valjoux-7733-7734-7736-technical-communication-service-manual-EBAUCHES-SA.pdf

 

   thanks; it looks like the top mvt. and has nivada on one og the bridges. nothing under the balance bridge.  724 nex to it.

[vinn3]

    i removed the balance,  de magnatized the hair spring and put it back in place.   it runs - a bit.  there is some power geting thru in the main spring.   my next step will be to remove the mvt. to clean the stem, case and the pushers.  i don't plan to work on it.   thanks for the help.   vin