Revue 73 timegrapher problems

[JohnC]

Hi all,

I am attempting to time a Wittnauer / Revue 73 manual-wind movement. It's meant to be a Christmas gift to my sister, so time is pressing.

After servicing, the watch runs decently with good amplitude. I've put the watch in beat visually, but the problem is that the timegrapher is telling me the watch is badly out of beat. However, the trace on the screen actually suggests it's not very out of beat at all. I also distrust the timegrapher amplitude reading, although I looked up the lift angle and set it at the "correct" 52 degrees.

What should I trust - the number on the machine, or my own eyes (and ears)? Many thanks. Photo attached.

Edited December 3, 2020 by JohnC

[JohnR725]

more than likely the numeric display is correct for the beat error. We've had this discussion somewhere in the discussion group this particular machine has a minor issue. The graphical display isn't big enough to actually show the maximum the machine can read of 9.9 ms. basically the graphical display is magnified so at around 4 ms I think it basically rolls over. So the lines can be close together as the number gets bigger and graphically it looks great but numerically it looks bad. Another problem with all of the timing machines is with amplitude if the amplitude is too low to read the wrong part of the waveform and a look much nicer than it really is. Then a course if you in a noisy signal that screws up everything he gives you very peculiar feedings.

Then helpful in these situations or basically good practice always look at your watch in more than one position. So you wind the watch up letter run around 30 minutes to stabilize. Time it dial-up then dial down and the wristwatch crown down would be good. Then give us pictures of all three of those.

Visually when you put the watch in beat what were you looking at? Then did you change the mainspring?

[JohnC]

Thanks @JohnR725 and good call. I always get heart palpitations whenever I have to manually adjust the beat, so I really did not want to do it. My usual practice is to line the regulator pins up with the pivot jewels. Then I remove the balance and with the assembly upside-down, note where the stud should be in order to line up the impulse jewel with the curb pin. That said, I don't like doing it because I've had quite a few tragic slip-ups with the screwdriver.

That said, this time no screw-ups. Got it down to about 0.2, which is more luck than skill. Amplitude looks about 300, which is what the timegrapher says. Positional error is a little much, which could be a hairspring issue or a heavy spot on the wheel. Max 0.3 change in beat error between dial up, pendant down, and pendant left (12 down). I think I'm gonna call this one done!

[Graziano]

Hello JonhC, also as well as above answer make sure you have no other working watches on the bench or near the machine. You would be very suprized how sensitive these machines are, and it will throw your readings 

 

Edited December 3, 2020 by Graziano