The end of an era, A7750 parts supply dried up...

[RWG Technical]

As we all know, individual parts availibility for the Asian movements, especially the 7750 is non-existant.

If you want spare parts, you do as I have done, you buy complete A7750's and tear them down for parts. At $125 per movement, this is not a cheap option and I can't afford to do it anymore.

As with any mechanical item, there are typically a few parts that cause all your problems. These problematic parts on the A7750 have been discussed at lenght already and don't need repeating in this post.

I want to draw your attention once again to one part that has been taking a beating lately, and it's only on the new version of the A7750.

The part I am referring to is the transfer gear between the mainspring winding gear and the autowinder gears.

This gear, like all movement gears, has a steel pivot and brass wheel. The steel pivot engages into the mainspring gear, and the brass section engages into the autowinder gears.

This gear is the one that will be damaged and stripped of it's teeth when handwinding the watch. What I mean is that this is always the gear that gets damaged if you handwind, and I don't have any more spare gears to replace them. As we all know the servicing and oiling of a factory delivered A7750 is terrible. There are two critical problems which are causing the handwinding gear damage:

1. The click or clutch gear that is directly connected to the rotor is sticky on an unserviced movement. This adds friction when you handwind the watch. The gear is a one way clutch and is supposed to slip and not turn the rotor when handwinding. If you feel the rotor spinning when you handwind, you have a sticky gear.

2. The small transfer gear between the click wheel and the mainspring transfer gear, is always gummed up and doesn't spin freely either.

On an unserviced movement the friction from these two gears is enough to cause the mainspring transfer gear to loose it's teeth when handwinding the watch. This damage can only come from handwinding, the gear will not be damaged by the rotor winding the watch.

I don't think this damage is being done on purpose by the owners, but keep in mind that the gear material is no match for your finger strength when you handwind. It only takes a slight turn to bend a tooth on the gear, once this happens, and before you know it, more teeth are damaged and the autowinder is not working anymore.

Last night I used up my one and only last mainspring transfer gear for a repair. The damaged gear had only two missing teeth (the owner will be sent back the old gear so he can see for himself the damage) and in this case, the owner never handwound the watch. I suspect that it was handwound and damaged before he took delivery.

How can you prevent this?

Easy, swirl your A7750 in your hand to get it going and set the time and wear it. I'm not selling or suggesting servicing as a solution, I am suggesting you avoid handwinding at all times, especailly on an unserviced watch. Once serviced the problems are corrected and slow and careful handwinding to get the watch started is ok. I handwind all my A7750's, all have been serviced, some going back 3+ years, and have not damaged a gear yet.

Of course all is not lost, if you end up with this problem you can always make your watch a handwind model...

RG

[FxrAndy]

Thanks for letting us know Rob

[Samurai]

Thanks mate. Really useful info.

[Mickey Padge]

Informative as always, thank you The Zigmeister!

I never wind my automatic watches, I do what that old dealer used to say and shake them like a mad cow

[Corgi]

Can't the community establish a connection with the manufacturer directly (perhaps through one of our well known dealers), come to some sort of understanding and build a mutually profitable relationship trading in specific movement parts only?

[JoJo35]

RG,

Thanks for taking the time to explain this to members. Hopefully your insight regarding these movements will help individuals avoid inadvertently damaging their watches

[scoobs1971]

Thnx for sharing this insight! I think a lot of people are not aware of this.

P.S. good to see you posting again...

[paulw]

Thanks for the info Ziggy.

As always a great help to us all.

[mikellem]

Rob, Thanks for the 7750 movement update...

[elisiX]

Well I will be sure to keep this in mind.

Thanks Rob.

[robertk]

I've taken your advice and only shake it. The problem for me is that sometimes I want to put it on a watchwinder since I have a large collection and don't rotate them frequently enough, and only shaking it, won't give it enough "juice" to keep it running on a winder.

[freddy333]

Ziggy -- Julesborel used to sell most of the 7750 parts, or is this specific part in the A7750 1 of those that differ from the ETA version?

For whatever it is worth, I have been manually winding this (asymmetrical pusher) A7750 approximately weekly ever since I received it from DW last year

In order to mimic the gen's manual wind movement & to reduce the movement's space requirements so I could fit the correct profile DW caseback (without the bottom of the caseback coming into contact with the pusher levers) I had to remove the rotor.

However, to mirror what Ziggy said, overhauling the auto-wind module was mandatory because of the state it was in when I received the watch. The auto-wind module was dismantled, all of the components were thoroughly cleaned in the ultrasonic & then everything was lubed & reassembled according to ETA specs. The difference, before & after, is something you can easily feel when winding the watch. Those who are familiar with the Lemania/Venus will know what I mean -- manually winding an A7750 after being overhauled feels alot like that, like butter.

Oh, and I am wearing her today.

[abat]

Good info, thanks. I stopped handwinding my A7750s when this came to light a while ago but I suspect I may have already done them damage.

[lanikai]

Thank you again R for your time... ever since your first thread on this issue.. I do not hand wind my A7750's .. well i give it a couple of cranks slowly just to get it going then move it around in circles a few times before putting it on .. it has enough power to run the rest of the day .. keeping on my wrist

Thanks again

R

[RWG Technical]

I have not tried an ETA gear to see if it will fit, so far most of the ETA parts I have bought for repairs of the A7750's have not been compatible with the Asian model.

May as well try one of these gears with my next supplier order, otherwise there are going to be a lot of handwinds from now on

RG

[magagne]

As we all know, individual parts availibility for the Asian movements, especially the 7750 is non-existant.

If you want spare parts, you do as I have done, you buy complete A7750's and tear them down for parts. At $125 per movement, this is not a cheap option and I can't afford to do it anymore.

...

Last night I used up my one and only last mainspring transfer gear for a repair...

RG

Z, I'll send you my Asian7750 21k mvt that I don't use (it come from my 3717 when it was replace by a GEN Swiss Valjoux7750), for all the help and great service you gave to me and contribution to us. You will be able to cannibalize it. You will be able to help one more member with it.

[astro]

The Zigmeister-

just bought this from tech and would like to have it fully serviced. Please contact me if you will do the work.

http://www.rwg.cc/members/index.php?showto...6681&hl=hbb

[Noel Fleischer]

On that note, wonder if a group buy for watch-winders is in order lol

i have stripped the hand winder gear on a bunch of eta non-chrono movements.

they are supposed to be 'swiss', but i nver had this problem with a gen.

i did go out and get a 4 winder watch case. i've had a bunch of those but

the motors seem to burn out with the heavier watches.

[freddy333]

For winders I've learned a few things:

1) Go with an upright winder. The inclined winders don't work well.

2) Go with a good warranty. If it craps out, like all electronics, it'll be in the first 6 months.

3) If you can hear it wind, it is the wrong winder. A good quality electric motor will be virtually silent.

Now you tell me!

Just this morning, after spending a good part of the weekend doing research, I bought 1 of these double watch winders (1 year warrantee)

[Guest]

my winder (quad) sounds like somebody inhaling a bong.....

Edited July 1, 2008 by jcmiro

[testhm]

Thanks for this usefull information!

[RobbieG]

Such a shame that such a major movement contender in all reps has this problem. Winding a watch should never have to give one fear of breaking it. I hope in the future the rep industry will find and use a better oiled/serviced movement out of the gate. I know for many rep buyers the notion of paying for a full chronograph service done right - even at a and inexpensive rate in addition to the cost of the rep is troublesome - especially if they bought the rep used and the service costs more than the watch. Service is much easier to justify when you have 5-10K of investment into the watch and there is rarely a need until the first five or so years of enjoyment has past. I know when those milestones are reached and I'm attached to the watch I sort of look forward to sending the watch to the "spa" so to speak. Plus the confidence is higher that after the service something else isn't going to break by happenstance causing the process to repeat for another expense.

I would love to hear from the members how they all feel about this issue - initial cost vs. mandatory service cost and where the line gets drawn. How much sunk into a rep is too much and at what point do you feel you have future confidence to justify spending the money. I personally don't have any Asian movements in my box right now, mostly for that very reason of future trust/comfort, but I'm always curious as to how the rest of you feel about this issue.

It is one thing to have to adapt to something imperfect by "jerk/swirl" winding a watch for fear of damage, but what if something else breaks and where do you come out if it does. I don't know what Rob (or other rep friendly mechanics) charge for servicing a chronograph, but it isn't an easy job so it can't be too cheap if done right. And $125 for that movement seems high if it still isn't right and reliable.

So do you get a whole new watch, pay for the $125 movement replacement, pay $600 or more for a 7750 or 7753 and labor to broach the subdial hands? And if you choose the Asian movement replacement or new rep route, do you pay for service right away or take your chances?