Unstable timegraph readings

[Lc130]

Hi All

I'm a beginner.  I ruined a hairspring on an otherwise fine bifora 115/1.  I replaced the balance, cock and all, from a donor (I broke off the curb pin in the original) .  Before the swap, the watch was stable on the time grapher.  Now I get varying readings.  I did demagnetize.

rate. amp, beat error

DU 

74, 250, 1.4

95, 228, 1.4

82, 249, 1.4

DD

70, 235,1.6

80, 250, 1.4

77 259, 1.4

PU 

100, 171, 3.9 

134, 180, 3.7

94, 205, 3.5

PD

-154, 197, 0.7

-73, 192, 0.7

-41, 198, 0.6

Any idea how I should proceed?  

Thank you

Charlie

 

 

 

 

Edited October 4, 2019 by Lc130

[watchweasol]

Hi Was the donor an exact match, Caliber  etc.

[Lc130]

Just now, watchweasol said:

Hi Was the donor an exact match, Caliber  etc.

Yes, as far as I can tell.  Both movements are stamped 115/1.

[watchweasol]

Hi  The fact that the origional was ok and the only thing changed was the balance complete with the cock would point to some discrepency in the donor balance. There are two ways of solving this  1 strip the donor balance and use the parts to rebuild the origional or    2   the purchase of a balance complete from the supplier of your choice.d

[Nucejoe]

I struggle interpreting timegrapher reults and often am wrong. I think the rate indicates imbalance wheel.  

[Nucejoe]

16 minutes ago, watchweasol said:

Hi  The fact that the origional was ok and the only thing changed was the balance complete with the cock would point to some discrepency in the donor balance. There are two ways of solving this  1 strip the donor balance and use the parts to rebuild the origional or    2   the purchase of a balance complete from the supplier of your choice.d

Aren,t hairsprings, balance wheel interchangable?

[watchweasol]

Hi  One would suppose that if the balance came from a donor unit of the same caliber that wold be the case. But the watch was working ok untill the balance was changed  which  points to the balance being off key.           

[Nucejoe]

Out of round balance wheel would cause variation in PU & PD positions. Poise issue is of the same nature.

If balance wheels weigh the same, the good HS + good balance wheel would work (simply interchangable).  In case of  different weight, there is still a chance to vibrate the two.

Have you checked the upper jewel assembly? Combine with excess endshake, they exacrebate the problem.

Best

 

 

[watchweasol]

Just a thought, did the donor watch work before you used the balance ?. If so put the balance back in the donor and checki it out on the vibrograph  it may have exibited this fault in the donor and you have transfered it to your watch.

[Nucejoe]

11 minutes ago, watchweasol said:

Just a thought, did the donor watch work before you used the balance ?. If so put the balance back in the donor and checki it out on the vibrograph  it may have exibited this fault in the donor and you have transfered it to your watch.

Suppose it dose exhibit the same fault, how would this new info help  diagnos the fault or fix it. 

[watchweasol]

It wouldnt diagnose the fault but it would prove that the balance assy was exibiting the fault before fitting to the recipient watch therefore a fault was transferred and was inherent in the donor watch before removal and refitting, There is no way of knowing if this was the correct balance that was in the donor in the first place.

[Nucejoe]

3 hours ago, watchweasol said:

It wouldnt diagnose the fault but it would prove that the balance assy was exibiting the fault before fitting to the recipient watch therefore a fault was transferred and was inherent in the donor watch before removal and refitting, There is no way of knowing if this was the correct balance that was in the donor in the first place.

Thanks for the explanation. I see now, it saves us a search in the wrong place. 

Best 

 

[Lc130]

7 hours ago, watchweasol said:

Just a thought, did the donor watch work before you used the balance ?. If so put the balance back in the donor and checki it out on the vibrograph  it may have exibited this fault in the donor and you have transfered it to your watch.

Thank you.  It worked but I only tested the dial up position on the timegrapher before transferring it.  Next week I plan move it back to the donor and test all positions.  

Charlie

 

[watchweasol]

Hi LC  Thats good. Once thats done and proved either good or faulty we are then in the situation where we have established facts and can move on. Problem with donor watches we have no history, some may have been cobbled together to sell regardless.  In terms a working watch is defined by the fact that the balance swings and it ticks, There may be a multitude of sins in the watch yet to be discovered.  when buying donor watches it is a case of buyer beware (caveat emptor), but we all do it knowing  most of the time it works the odd time it doesnt.