Valjoux 7750 Advice/help

[CKelly]

Hi Guys,

    Tonight I find myself in a state of puzzlement and am asking for a little help and advice. Recently I have found that I really enjoy working on the 7750 movement. After rebuilding 3-4 I find that I have managed to accumulate a small collection of spare parts. Last week I decided to buy a few more and build another. For general information this particular movement is marked Val 7750 rather than eta 7750. I've got it running well but do have an issue with the hour counting wheel. For some reason it wants to run all the time. I have replaced that wheel with a new one and even replaced the hour counter lock but neither helped. When I activated the chronograph and then reset it the hour counter will reset to proper position but will just keep on running from there. I have also got a new hour hammer spring installed as that was one of the parts I needed anyway. Any ideas would be appreciated.

Thanks,

Charles K 

[clockboy]

I have not worked on one of these yet but will be soon. It sounds like a return spring issue. I know Mark very often makes replacement springs for Chronographs so I guess this is a common issue.

[Geo]

Hi Charles, I've just been having a good look at the 7750 hour wheel assembly and it looks like it has a slipping clutch built in it to transmit drive to the hour hand.

If that clutch is too tight, the hour wheel brake may not be strong enough to resist this drive force to prevent it from rotating. I would assume that this clutch should be lubricated in such a way that it slips very easily when the brake is applied.

Is the lower pivot hole for the hour wheel worn?

These are just ideas, as like Clockboy I haven't worked on one.

Edited March 5, 2015 by Geo

[JohnR725]

For those of you who have never worked on one of these watches before the Swiss have something helpful. The first link below takes you to a step-by-step guide to how to disassemble and reassemble and adjustments.

 

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

 

On this link all four watches that they have a step-by-step guide is listed.

 

http://www.eta.ch/index.php?id=161&L=2

 

Then the absolute must have is the service manual. You can find it at this link click on the technical documents. Then rather than do a search if you look at option number one on the right-hand side it says caliber with a downward arrow click that and it will give you the complete list.

 

https://secure.eta.ch/csp/DefaultDesktop.aspx

 

[Geo]

Excellent post as usual John, now filed for future use! :)

[clockboy]

I have visited the ETA site many times and it is really informative, I wonder if this site will still stay up after November this year.

[JohnR725]

I have visited the ETA site many times and it is really informative, I wonder if this site will still stay up after November this year.

I've already noticed that their stuff missing off the site.  For instance a lot of times they used to have the manufacturing information sheet which had all sorts of interesting things other than manufacturing..  Such as the timing specifications the rates the watch should do etc. and they are no longer available. Then it doesn't look like they've added anything new Other than at least they've updated their tech sheets.

[PeterGe]

I have visited the ETA site many times and it is really informative, I wonder if this site will still stay up after November this year.

 

What will happen in November?

[clockboy]

The Swatch hammer blow. No more replacement parts or movements to the general trade. The biggest worry is Swatch also own companies that manufacture Jewels,Springs,batteries & a host of other watch parts. If this company was based in the UK it would have been stopped a long time ago by the Monopolies commission.

Edited March 6, 2015 by clockboy

[PeterGe]

That's seems like a huge problem. I did know they were restricting some parts (e.g. circuits) but I didn't know they would completely stop providing parts.

If this is actually going to happen, at first parts (still in stock) will become very expensive and after that???

No more repairs for independent watchmakers?

 

I hope it won't come to that as I'm slowly building up my business & hoping to do it on a full time basis.

Edited March 6, 2015 by PeterGe

[Geo]

I hope it won't come to that as I'm slowly building up my business & hoping to do it on a full time basis.

I wish you well with your business venture Peter, but I think you may have to learn to speak Chinese!

[clockboy]

Peter write to ETA and ask, I have many times. I have not received an answer yet but will still keep writing. If you are based in the UK write to your MP, in Europe write to industry minister. The more letters the better for all. The BHI are in talks with the Swiss but no progress at present if no progress by end of April I will send letters to Watch Dog (UK TV) newspapers, MP,s & our industry Secretary. I will be a pain in proverbial **BLEEP** (more than usual) until I get answers the more that join the debate the better. There is nothing to loose at the very least the general public should be made aware.

[JohnR725]

To get a grasp of the consequences look at the website below. They been slowly absorbing practically everything in sight. So besides the availability of spare parts being threatened other stuff gets threatened like would they ever stop selling moebius oil for instance?

 

http://www.swatchgroup.com/en/brands_and_companies

 

http://www.swatchgroup.com/en/brands_and_companies/corporate/swatch_group_research_and_development/moebius

 

Then there’s the interesting consequences of this such as the company below. To fill the void of companies leaving, they make movements. As this discussion is supposed to be about the 7750 look at the SW 500 it’s supposed to be equivalent.

 

http://www.sellita.ch/intro_english.html

[Geo]

Hi Guys,

    Tonight I find myself in a state of puzzlement and am asking for a little help and advice. Any ideas would be appreciated.

Thanks,

Charles K

Are you any nearer solving the problem Charles?

[bobm12]

I'm curious too about the problem too and following this thread.

 

Cheers,

 

Bob

[CKelly]

Hi all,

   So far I have left the watch alone for a day or so. Repaired a Tag for someone at local jewelry store and have been thinking about valjoux. Once you put calendar bridge on you can't see the action of the hour wheel. What I've done is to try to visualize how things went together as I was assembling. I remembered the hour wheel may have been sitting too high on the main plate. I think it is so high that the lock may not actually hit wheel. Tomorrow I'll take it apart and check on this theory. I kind of thought about this after reading Geo's post when he mentioned the lower pivot hole. After I check that I'll let you know what I find. What I'll do this time though is put calendar bridge on and then put a hand on hour wheel and check out watch before installing dial and all the hands.

 

Thanks,

Charles K  

[Geo]

Hi Charles, thanks for the update. It's not a bad thing to leave it for a few days before starting again, my fingers are crossed for you. :)

[CKelly]

Hi all,

   Well I had to work today however when I got home my wife was out shopping so it was a perfect time to check out the valjoux. When I took it apart the hour counting wheel moved some. I repositioned everything and looked at lock and wheel and it did appear as if wheel was too high, possibly not going not going all the way into the lower pivot hole. I had an old hour counting wheel and tried that to see how it fit. Looked like a perfect fit. Now I'm scratching my head wondering why the new part didn't fit properly. I put the old counting wheel in and put everything back together. That was about three hours ago and so far everything is perfect. Now all I have to do is wait for the oscillating weight I ordered to arrive.   Thank you Geo for saying something about that pivot hole. As soon as I read that I started remembering the wheel wanted to lean a bit when in place but to make contact with the lock it has to sit very close to the plate and doesn't have room to lean much.

Thanks,

Charles K

[bobm12]

Hi Charles,

 

I had the same problem with a Seiko escape wheel I ordered from cousinsuk. It was too high and apparently it was supposed to be correct (came in the Seiko box and all). I popped it the old escape wheel and it is working fine...I wonder if manufacturers do revisions and forget about the old originals...

 

I'm glad it is all well now with your 7750!

 

Cheers,

 

Bob

[Geo]

That's good news that you've solved the problem Charles! :)

[clockboy]

Interchangeably of parts have caught me out a couple of times. They look the same but sometimes as Charles has found there are sometimes slight mods.  

I have not looked at the 7750 sheet but on the ETA tech sheets there is normally on the back page updates & mods listed. 

[HorologicalHobby]

Is it running constantly as soon as the chronograph starts and is then paused? If so, the plastic, L shaped clutch is worn. You can make it wider with a staking set (just gently hit the edge that engages the wheel). I had that issue with my speedmaster auto, and that's how the watchmaker fixed it.

[CKelly]

Hi,

   Yes the hand was running all the time but when I was putting the watch together I had to buy a new hour lock as I didn't have the old one. Changing out the hour wheel fixed mine. The hour wheel I was trying to use would not fit properly into the lower pivot hole which meant the lock was sitting lower than the wheel and would not make contact when chronograph function was not in use. Anyway I've got it running well now but I do appreciate the tip.

 

Thanks,

Charles K

[CKelly]

Hi,

   Sometimes you think you have solved an issue only to be tricked. After I changed out the hour counting wheel my watch ran well for several days and then for seemingly no reason the hour counting hand took off running again. When I took the watch out of the case to check it out again I looked at the movement from the side before doing anything and noticed that the hammer spring had worked its way slightly under hour hammer operating lever. That meant there wasn't enough pressure on the spring to hold the lock up tight against the hour counting wheel. The operating lever was actually off its pivot as was the hour hammer. Saw that when I removed the calendar platform. I started thinking that there must surely be some way to hold these parts down and I checked out another calendar platform I had. This other platform was milled in such a way as to prevent the operating lever from raising up and now to problem is really solved. I'll post some pictures later as this was something very strange.

Charles K

[CKelly]

Hi,

   Well so much for the picture of the strange gap. I put the old platform on another mainplate and it fit perfectly with no gap. I'm not sure what went on originally but I couldn't take out the gap until I changed out the calendar platform. Anyway there's no gap now and watch is running perfectly. I did promise a picture though so here is what the finished watch that I put together out of bits and pieces looks like now. I did buy the dial and case but I wanted it to look nice.

Charles K