7750 headache

[nicoyenny]

HI all!

I have this weird problem with a watch I built for a friend, he told me to build it using an Asian 7750. I didn't want to, but oh well, I went and bought the "latest" version of the A7750 hi-beat, etc..

I finish the watch (first I took the movement apart and did a cleaning/rebuild/oiling). Aside from the parts being "flimsy" it wasn't out of the ordinary ...

It looks GREAT on the timegrapher (0.0s, great amplitude, ~ +2 secs/day) , yes, I did set the lift angle to 49 deg.

BUT the watch actually runs incredibly fast, it is gaining about 1/2 hour every 10 hours (!) . I did demagnetize it just in case but it didn't help.

Am I missing something?

[jeffc83]

My guess would be that the hairspring is touching something or even sticking to itself.  Check to see if it is true and the spring action is clean.

Edited May 24, 2016 by jeffc83

[nicoyenny]

That's one of my thoughts, it looks ok, but I will pull it tonight and do a one drop clean ...

[HorologicalHobby]

So if it reads right on the timeographer, it sounds like a canon pinion, or offset canon pinion issue. 

[matabog]

check the wheels and pinions teeth number and their ratios. calcul

Edited May 25, 2016 by matabog

[matabog]

http://watchguy.co.uk/repair-heuer-autavia-buren-12/

 

same issue

[vinn3]

did you demagnetize the balance or the whole  watch?

[nicoyenny]

WOW!

Thanks for all responses, yes, a disassembly is on the works, escapement is perfect, and as mata said, I suspect the canon pinion might be the culprit. I am 85% confident (yes, I quantify my confidence) that I installed an ETA canon pinion, and doing math I see that there is an extra tooth somewhere ... time to pull the microscope . Of course, it won't happen until Friday...I am xtra busy for the next two days ..

On hindsight I should have pushed my friend to spend a little more and let me get an ETA ... well, practice makes perfect ....

[jdm]

8 hours ago, matabog said:

http://watchguy.co.uk/repair-heuer-autavia-buren-12/

Christian is a top notch watchmaker and one can only learn big time from his way of thinking and doing.

Edited May 25, 2016 by jdm

[noirrac1j]

43 minutes ago, jdm said:

Christian is a top notch watchmaker and one can only learn big time from his way of thinking and doing.

Thats a fantastic link, @jdm. I've read several overhaul "stories" from this guy. They're very useful as references because of the knowledge base, and the guy also takes excellent pictures. Great methodology.

JC

[matabog]

I'm not saying it's not the canon pinion, but I was  suspecting one wheel in the wheel train. If it were the canon pinion, then the error in timekeeping would be much bigger.

Edited May 26, 2016 by matabog

[noirrac1j]

27 minutes ago, matabog said:

I'm not saying it's not the canon pinion, but I was  suspecting one wheel in the wheel train. If it were the canon pinion, then the error in timekeeping would be much bigger.

This is correct...and when its the cannon pinion it would likely be losing time.

JC

[nicoyenny]

Thanks!

Yes, I will inspect every wheel in the train ... I used a few ETA parts on the build, so there are a few suspects ...

Will report back when I find the culprit. (perhaps the second wheel, that is the one in the wheel train that I replaced for an eta version (!))

[matabog]

Bingo!

[noirrac1j]

what did you find?

JC

[nicoyenny]

Nothing yet!

I will do the disassemble/reassemble tomorrow or Saturday ...WAY too busy with "regular" work (the one that pays the bills )until tomorrow
 

[matabog]

Whell?

Edited June 1, 2016 by matabog