Phasng Issue
 
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Thread: Phasng Issue

  1. #1
    WTF Veteran Time2Fish's Avatar
    (Retired Engineer. Pratt Whitney Aircraft)

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    Default Phasng Issue

    I have a watch I am trying to phase. Fingers are aligned properly. Drop off I have had to estimate because the Tuning Fork does not pull back enough to see when it would theoretically pull off the index wheel but I believe it is close to the 6 to 8 tooth number. The problems that I have are:
    1. When low voltage phasing, the index wheel does not stop turning when going from 1st to 2nd phase or any phase for that matter. Current is well within the OK range for 1.55 volts.
    2. If I ignore the fact that the index wheel is suppose to stop between phases, once the movement is spinning at normal speed and I case the movement with a 1.55 volt battery, the watch gallops.
    3. The Vibrograf reading is -5.6 seconds which is low but well within regulation limits.
    4. When I try to High Voltage Phase, the index wheel DOES stop between phases at the 1.055 volt reading, but, when I increase the voltage to 1.75 volts, I can not slow down the index wheel unless I go way past the lower voltage finger setting. Current at the 1.75 volt input is high at around 10 microamps.
    5. Low Voltage Phasing is being done at the Low Amplitude Setting and High Voltage Phasing on the Read Microamperes Setting.


    So:
    a) The Vibrograf is telling me that I the fork is vibrating correctly and that I should be losing 5 to 6 seconds per day as long as the watch is phased correctly. Right?
    b) No hesitation between phases during LVP is telling me what? I am stumped.
    c) The fact that I can get the movement to run at the right speed when Low Voltage Phasing, but, when cased, the movement gallops with a 1.55 volt battery battery installed is telling me what?

    AS always, thanks for the help.

  2. #2
    WTF Full Member Chris Radek's Avatar


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    What's your amplitude at normal battery voltage? If it's much above 2 teeth, you won't be able to stop the gallop.

    Set your amplitude to a little more than one tooth, and phasing should be easy, start and stop should make sense, depending only on the phase screw, and not on the wheel rotation. If it doesn't feel right, check for endshake and if it's ok, just replace the wheel, it's bad.

  3. #3
    WTF Veteran Time2Fish's Avatar
    (Retired Engineer. Pratt Whitney Aircraft)

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    It looked to me like the amplitude was about 1 jewel thickness with the Watchmaster 600 set at low amplitude and 1.5 volt input. So that is about 2 to 2.5 teeth? Anyway, I reduced the input voltage to .9 volts where it looked like the amplitude was 1 tooth, and adjusted the phase screw. Doing this was easy to get the movement into 2nd phase. I then increased the voltage to 1.5 volts and everything looked to be running as it should with no adjustment necessary. I tightened up the pawl finger and recased the movement. Running now very well and will check accuracy against the NIST this afternoon.

    This seems to be 180 degrees opposite of what I normally do. Usually I can get into second phase with 1.5 volt input and decrease the voltage making tweek adjustments until it no longer runs.

  4. #4
    WTF Veteran Time2Fish's Avatar
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    Well in 3 hours the watch gained 30 minutes so I still have a problem. I believe my problem lies with the amplitude so I am going to replace the coil and see what happens.

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