ETA Valjoux 7750 questions

[Danh]

Evening folks 

decided I wanted a project and it was going to building a watch at cost, picked up everything I needed from various places around the planet.

i picked up a 7750 movement cheaply (so expected some surprises as the movement is a genuine Swiss one).

Assembled the watch, and during the process noticed a couple of irregular things with the operation.

I am hoping if I post a list you may be so kind as to point me at what to look for when I disassemble to sort. 

1. When the stem is removed the watch sometimes stays running

2. When the chronograph is reset the hour counter does not reset when the minute and second counter do.

all good fun, and loving the adventure, plus the watch looks lovely with the sapphire back and diver case.

thanks for your time folks 

[HorologicalHobby]

1: Is this pulling stem out to set the time, or pulling the stem out completely?

If it's the first, then yes the watch should stop if it has the hack (which I believe is standard on all 7750's), however it will keep running if you just pull the stem out completely.

2. That's very weird, could be an issue with the hammer on the dial side that resets the hour function, or it could have a damaged, dirty, or wrongly lubricated hour counter. Do you have a picture of the dial side under the calendar works? 

[MortenS]

1. Sounds like the stop lever "hack" is not centered with sliding pinion. 

2. I have seen it before when the hour hammer spring is assembled the wrong way.

Morten

[noirrac1j]

8 hours ago, Danh said:

Evening folks 

decided I wanted a project and it was going to building a watch at cost, picked up everything I needed from various places around the planet.

i picked up a 7750 movement cheaply (so expected some surprises as the movement is a genuine Swiss one).

Assembled the watch, and during the process noticed a couple of irregular things with the operation.

I am hoping if I post a list you may be so kind as to point me at what to look for when I disassemble to sort. 

1. When the stem is removed the watch sometimes stays running

2. When the chronograph is reset the hour counter does not reset when the minute and second counter do.

all good fun, and loving the adventure, plus the watch looks lovely with the sapphire back and diver case.

thanks for your time folks 

You're gonna have to open it up and disassemble.Tha hack  lever should be lubricated with a couple of drops of Moebius D5  on the plate and @MortenS is right: the hack has to be properly seated in its slot and coupled to the sliding pinion so that it does its job when the crown is pulled out.

For the other problem...is the hour counter just NOT resetting or is it resetting improperly? If its not resetting check the alignment of the hour counting wheel:

http://www.eta.ch/swisslab/7750/7750.html

 

The hour counter lock, spring, lever and hammer also have to be properly positoned:

http://www.eta.ch/swisslab/7750/7750.html

I know its a bummer to have to take it apart again, but if you want to fix that problem you'll have to.

J

Edited May 20, 2016 by noirrac1j

[clockboy]

Agree with J it is an assembly issue so you will have to strip & investigate. Mark has a vid ion the 7750 also there was a assembly & disassembly charts o the ETA web site.

[Danh]

Thanks for all the answers guys, really appreciated, and loads to go on

i have watched Marks Video, but will watch it again a few times (my wife thinks I am strange )

it is a couple of days before I have a chance to do it, but will report back

once again, thank you

[noirrac1j]

7 hours ago, Danh said:

Thanks for all the answers guys, really appreciated, and loads to go on

i have watched Marks Video, but will watch it again a few times (my wife thinks I am strange )

it is a couple of days before I have a chance to do it, but will report back

once again, thank you

Go slowly and methodically....the valjoux is unforgiving.

JC

[Danh]

Thanks JC, point taken

i have a couple of tools to buy before I start, lots of research in the meantime 

[Danh]

15 hours ago, noirrac1j said:

You're gonna have to open it up and disassemble.Tha hack  lever should be lubricated with a couple of drops of Moebius D5  on the plate and @MortenS is right: the hack has to be properly seated in its slot and coupled to the sliding pinion so that it does its job when the crown is pulled out.

For the other problem...is the hour counter just NOT resetting or is it resetting improperly? If its not resetting check the alignment of the hour counting wheel:

http://www.eta.ch/swisslab/7750/7750.html

 

The hour counter lock, spring, lever and hammer also have to be properly positoned:

http://www.eta.ch/swisslab/7750/7750.html

I know its a bummer to have to take it apart again, but if you want to fix that problem you'll have to.

J

Love the animations, and the info, thank you

[noirrac1j]

You're welcomed.

JC

[Danh]

I have another question before I take it apart if you would be so kind

is it easy to fit a day wheel to the movement? As far as I can tell I need the date wheel, day jumper, day star driving wheel, and a spring (that I have not managed to source yet)?

is this possible? And did I miss anything ?

thanks

[noirrac1j]

Before I say "its not hard at all'," do you know how to uncase the movement, remove all of the hands, and remove tge dial? If yes then it'll be easy to change the day and date wheels and all related mechanism.

JC

Sent from my SM-G925T using Tapatalk

[Danh]

Hi JC, 

Already uncased it, can remove the hands no problem, removing dial is fine (I fitted it when I built it)

i have to strip it anyway to see why the hour counter is not zeroing, so am contemplating adding the day wheel. (And changing the dial of course)

tried googling it and found mixed answers on the subject, so I thought best to ask the experts 

[nicoyenny]

Check the 7750 service walkthrough on the forum ... read it 3-4 times so you understand the steps, adding the day wheel is not difficult, but it depends on how patient you are and please, don't drink coffee before attempting

http://www.watchrepairtalk.com/topic/2309-eta-7750-service-walkthrough-the-industry-standard-chronograph/

[Danh]

Thanks, no coffee, got it 

[Danh]

I stripped the 7750 today, really enjoyed it, it turned out the Chrono hour counter needed the parts stripping and lubricating as per the specification.

i decided to not fit the day wheel as I wanted to use the red dial I picked up.

great fun project, thanks to all that helped

 

[SSTEEL]

Congrats, how long did it take you to refit the oscillating pinion?  My first time was a trying experience.

[Danh]

I did not have to strip down that side to solve the current issue.

I am now totally addicted though, so will probably buy a 7750 movement for repair from somewhere so I can do a complete strip and rebuild.

i love the mindfulness of the process

[noirrac1j]

Great job!

 

JC