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Posted

Hi,

I am new to this forum, and a beginner in watchmakig as a hobby. Recently i bought a timing machine to check the accuracy of an old Pronto watch (CAL. 2750). I tested the watch, it was running around 45 seconds fast and the beat etter was high. I then tried to adjust the beat error on the watch by adjusting the stund on the balance. 

Tested the watch again, and it was running crazy fast, around 900 sec+ a day. I have tried to demagnetize the watch, and it is now running at different rates between +240 to + 450. The balance spring looks fine in my eyes, no touching parts. Can anyone hjelp me find the fault? 

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Posted

Hmmm... tricky. Did you take a picture before you adjusted it?


I suspect the hs is now catching on the slot in the rate adjuster, or the  hs has been deformed slightly and coils are touching, or the hs is now dirty for some reason. Also check the balance pivots are still intact.

Posted

I agree with Andy, HS issue.

Faulty HS end length, or the slit catches/ carries the HS. 

Move the adjust arm all the way towards the stud, that is max HS length activation. Readings on timegrapher should not vary then. 

 

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Posted (edited)

if it is running fast and has a beat error then the watch will need be adjusted not regulated. regulating (moving regulator stud to fast or slow) will not correct beat error. beat error occurs when the balance wheel will rotate lets say 360 degrees in one direction, then 270 degrees in the opposite direction. Normal osculation should be about 270 degrees in both directions. 

1. Observe the HS and BW under a strong eye loop. Is the the BW moving in fast short strokes (usual cause is magnetism), or is it moving wildly fast in long strokes. best way to see this is if you have a smart phone with slow motion feature record the BW then watch it in slow motion and you can get an idea of the degree in rotation and get an idea which direction is off. also under magnification watch the HS coils expand and contract, are any of the coils sticking, is the HS riding up or not laying completely flat.

2. Demagnetize the movement and balance assembly separately. remove pallet and cock and reinstall balance asbly. make sure the roller jewel rests in the middle of of the banking pins. if it does not then there is your "beat error" problem. you will have to adjust the HS collet on the BW untill that roller jewel is dead center in the banking pins. there is a way to do this with spring attached but that requires experience so HS will have to come off. remove the stud from the cock and observe how the HS sits on the BW, make sure there are no warped or sticking coils. if all is good then make your adjustment and reattach stud. time the watch again and see if there is any issues.

3. If there are still timing issues then a full service is in order. pivots will need to be checked for deformities and/or wear. picot jewels will need to be stripped and cleaned of old oil and debris, etc. End/side shakes of the BW should also checked before service begins.

A TIMING issue is a sure sign that a SERVICE is in order, so I will recommend a full service either way for this watch regardless of what the fault is. But I always like to do some fault finding first (things mention above) then proceed with the service, you will also be doing other quality control inspections during the duration of the service. i.e checking pivots, pivot jewels, mainspring, pinions and teeth, end/ side shakes of train, etc.

 

demagnetize the the movement and

Edited by saswatch88
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Posted
2 hours ago, Nucejoe said:

I agree with Andy, HS issue.

Faulty HS end length, or the slit catches/ carries the HS. 

Move the adjust arm all the way towards the stud, that is max HS length activation. Readings on timegrapher should not vary then. 

 

HS end length is correctly shaped if collet stays right on top of the jewel hole, as you move the adjust arm through entire HS end length. If badly shaped you vary the conditions on HS as you move adjust arm.that is;  at one adjust position you may advance the impulse jewel while at anthor postion of adjust you retard. In other words you would be introducing error to the impulse jewel position while trying to adjust.

Not to mention other problems, improper HS shape brings.

That I think is what andy refers to, he is thinking. drastic difference reading could easily be due to the HS shape altering at dif adjust position, all due to bad  shape of HS end length or unsmoothness there.

I have a question to ask of andy,  How do interpret the change in slope of the gragh?

Thanks in advance.

 

Posted

The HS coils may be sticking intermittently, this typically results in a wavering graph. There may be some issue with the power train, dirt or damage, which can also show a wavering result, or the oscillator may be so far out of beat, that it has some secondary component to its oscillation. If you check Mark's videos, they may help.

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Posted
On 3/30/2019 at 12:40 AM, AndyHull said:

Hmmm... tricky. Did you take a picture before you adjusted it?


I suspect the hs is now catching on the slot in the rate adjuster, or the  hs has been deformed slightly and coils are touching, or the hs is now dirty for some reason. Also check the balance pivots are still intact.

Hi, sorry, no picture before i adjusted it. The hs looks good, will try to clean it and see if it helps.

Posted
On 3/30/2019 at 8:58 AM, clockboy said:

Have you fitted a new mainspring. The hairspring looks good it is just running way to fast.

No, still the same mainspring. 

Posted

Thanks for all the replies! Have tried to demag the movement (hairspring and movement separately). The hs looks good, can´t see it touch anything. This movement has not been cleand by me, so will try to do a full service and see what happens. Think i have to adjust the watch in beat as well, so will do a full service, adjust and cross my fingers. Thanks to all of you!

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Posted
9 minutes ago, espenbd said:

Thanks for all the replies! Have tried to demag the movement (hairspring and movement separately). The hs looks good, can´t see it touch anything. This movement has not been cleand by me, so will try to do a full service and see what happens. Think i have to adjust the watch in beat as well, so will do a full service, adjust and cross my fingers. Thanks to all of you!

update the forum on your progress

Posted

1- Dispower the barrel at the click.

2- move adjust arm through the entire end length of the HS, ( from max retard,  to max advance) if that causes the BW move at all, the end length is wrongly shaped, In which case you are varying the impulse jewel beat as you move the adjust arm.

The impulse jewel should stay in beat as you move adjust arm.

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Posted
On ‎3‎/‎30‎/‎2019 at 12:58 AM, clockboy said:

Have you fitted a new mainspring. The hairspring looks good it is just running way to fast.

    if the balance is not magnetized,  put the regulator  in middle position and bend the hair spring till it is in beat.  there are books that show you how to do this.  vin

Posted
On 4/2/2019 at 6:08 PM, Nucejoe said:

1- Dispower the barrel at the click.

2- move adjust arm through the entire end length of the HS, ( from max retard,  to max advance) if that causes the BW move at all, the end length is wrongly shaped, In which case you are varying the impulse jewel beat as you move the adjust arm.

The impulse jewel should stay in beat as you move adjust arm.

I finally had some time to work with my watch today. Tried Nucejoe’s tip quoted above, but the BW did not move. As some of you suggested, i decided to clean the  balance only, before starting a full service. After some time in OneDip and drying, i started reassembling the balance and adjusting the watch in the timegrapher.

The watch beat is now looking good! The time is also a lot better now, haha. My only concern is the amplitude, it’s really low.

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Posted (edited)

Assuming the watch is fully wound, I would suspect the low amplitude may be associated with a weak or dirty mainspring, or dirt somewhere in the power train.

Edited by AndyHull
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Posted

you have friction somewhere, most likely due to dirt and/or dry pivots/mainspring. this watch needs a full service. new mainspring, cleaning and proper oiling. the watch is still slightly out of beat a little more work and it will be good to go

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Posted

I add power to the barrel manually. Just push to turn the barrel in direction it supplies power, If the amplitude flies, power supply is to be checked and MS tested.

If the amplitude remains the same or BW locks up ..etc, the issue is with the escapement.

Also check if end stones push on pivots.

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Posted
23 hours ago, AndyHull said:

Assuming the watch is fully wound, I would suspect the low amplitude may be associated with a weak or dirty mainspring, or dirt somewhere in the power train.

Yes, it was fully wound. 

1 hour ago, saswatch88 said:

you have friction somewhere, most likely due to dirt and/or dry pivots/mainspring. this watch needs a full service. new mainspring, cleaning and proper oiling. the watch is still slightly out of beat a little more work and it will be good to go

Thanks, will do a full service when i have time to sit down with this project!

35 minutes ago, Nucejoe said:

I add power to the barrel manually. Just push to turn the barrel in direction it supplies power, If the amplitude flies, power supply is to be checked and MS tested.

If the amplitude remains the same or BW locks up ..etc, the issue is with the escapement.

Also check if end stones push on pivots.

Wow, nice tip! Will definitly check this out, before starting a service. 

This forum is great, thanks to all of you! I’m learning a lot.

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Posted

Needless to say, the slight amout of power to add is what we feel the power source fails to supply. Strongly pushed the escape will lock.

I agree with saswatch on both counts, friction and slightly out of beat. 

 

 

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Posted
3 hours ago, Nucejoe said:

Needless to say, the slight amout of power to add is what we feel the power source fails to supply. Strongly pushed the escape will lock.

I agree with saswatch on both counts, friction and slightly out of beat. 

 

 

yea good idea nuce! force power through the mainspring. best way to do this i would think is fully wind it then push on the ratchet wheel with pegwood and hold it, dont let it seat back into the click. see if amp goes up and then see if it drops when you let it go and ratchet sits back into the click.

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Posted

I

1 hour ago, saswatch88 said:

yea good idea nuce! force power through the mainspring. best way to do this i would think is fully wind it then push on the ratchet wheel with pegwood and hold it, dont let it seat back into the click. see if amp goes up and then see if it drops when you let it go and ratchet sits back into the click.

I like your approach for being more suitable especially when the movement is assembled mounted on move- holder and to the TG.    Regards

 

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Posted

A little update:

Stripped down the movement, cleaned the pivotholes with pegwood and ran the parts in the ultrasonic cleaner.

I then lubricated the old mainspring and put it back together. Assembled the wheels and bridge and oiled the pivots. That’s all for now, and i think the wheels are spinning good. Will keep you updated.

On the last picture, movement before cleaning to the left, cleaned to the right.

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