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Venus Felsa 751, low rate after servicing

  1. sokard Jun 13, 2020

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    Dear Omega friends,

    I have been restoring a Venus with Felsa cal.751 and while I get all the readings in the timegrapher satisfactory, I can't set the rate to go more than -180 sec/day.
    When the regulator pin is at middle of he balance bridge I get around -700 sec/day and at the most advance position I can set it the reading is around -180 sec/day.
    The movement has been cleaned thoroughly and inspected and all seemed fine.

    Any opinions anyone?

    Thanks in advance.
     
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  2. Canuck Jun 13, 2020

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    Sounds to me like the roller jewel hitting a pallet horn on re-entry, causing a rapping sound.
     
    JimInOz likes this.
  3. JimInOz Melbourne Australia Jun 14, 2020

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    Let the mainspring down until its dead, then give it just enough to get the balance ticking and see if the balance/pallet/escapement behave normally.

    If they do, give the mainspring a bit more power until you notice problems.

    Your mainspring may be too strong, but I'm just guessing.
     
  4. ChrisN Jun 14, 2020

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    Do you have the lift angle set correctly as 332 degrees amplitude is high?

    If it's running slow:
    Did it run OK before you serviced it?
    Did you change the balance or hairspring?
    Is the regulator pin gap reasonable?
    Is the hairspring between the regulator pins correctly?

    This could be a lot of things so, check it as Jim says and see if it behaves at lower amplitude.

    Cheers, Chris
     
  5. Canuck Jun 14, 2020

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    Seems to me I recall the watch is losing, not gaining. If it was gaining a lot, I would suspect an incorrect mainspring.
     
  6. sokard Jun 15, 2020

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    Thank you all for your replies,
    To answer Chris's questions, the watch was running before service but the readings were erratic.
    I have checked multiple times everything that has to do with the balance and the hairspring and didn't find anything abnormal.
    I let the mainspring down and gave it power slowly as JimInOz said but again no difference.
    Finally today I inspected more closely the pallet fork and I think I found the cause of this problem.
    One of the pallet stones is broken on one side ( I missed that on my primary inspection:()
    Parts are already on their way so I will update once I receive them.
     
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