Mido 607 P movement balance spring removal

[Hirst]

Hello WRT community,

I am working on a very small 607 p auto winding movement.  These may be the smallest auto winding movement  made.  I have three of these movements and I've done the breakdown cleaning and assembly.  The movement in question is running very fast + 10 min of more.  The fine adjustment just does not work.  I am suspecting balance spring issues.  From top view the coils seem too tight on one side and may touch.  How does one remove the balance wheel and spring from this set up?  It's not the common screw held spring end.  Does this u pin slide out to remove the spring.  I have de-magnetized,  and checked to see that the impulse jewel is centered.  If the u-pin releases the spring, is this difficult to reassemble?  BTW the Balance wheel is 7 mm in diameter.  The red arrow points to what I'm calling the u-pin.

Thanks in advance,

[jdm]

I'm not sure about the U pin, maybe you could try a minor correction from below without removing the hairspring.
I advise you not to let dangle the balance, and not to use a tack, especially with minuscule and delicate hairsprings like this, as that will distort them and espose to risk of accident.

[Plato]

Google 'Incastar' for info. I think that's what you have there. I only have a model because I collect Incabloc advertising.

[watchweasol]

A Mido 915 uses the same roller adjuster/incabloc sysyem.  Have a look at Ranfft mido 915 for a clear picture and useful data/

[Plato]

It's already been dealt with a few years ago...

[Nucejoe]

 Flip the cock& balance upside down to see and show how hairspring is held, you shorten/ lengthen the free sprung by turning the roller, it should at end of the spring release it. 

9 hours ago, Hirst said:

  The fine adjustment just does not work.  

Do you mean turning the roller does nothing? 

 

[Hirst]

Hello WRT posters,

Well I examined this assembly carefully and reviewed post from the past.  Turns out that the the balance spring is truly free.   The u-pin does slide out allowing the two rollers to open and the spring can be slipped in. There is not fixed end to these springs.  I have two of these 607 Mido movements. The four pronged adjuster on top directly rolls in or out the spring length. On one I actually adjust too much and forces out the hair spring.  Both had distorted hairsprings and therefor could not be timed.  After some YouTube study,  I corrected the hair spring symmetry with instruments i fashioned from safety pins.  Centered the impulse jewels.

The work paid off.  Timing on one movement so far is great.  Whew!