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VMSG

How to replace hands on A79350?

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VMSG

Hi,

I have the IWC PORTUGUESE CHRONO with A79350 movement that I got from Mary.

The hands look weird with some stains on it and I want to replace them new hands, but I could not find any manual how to handle the A79350 movement.

I'm a total noob in watch repair and I don't know if this is over my head to replace hands on a chrono movement, so please advice me how and also if I should do so :)

Thanks!

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Glaude
7 hours ago, VMSG said:

Hi,

I have the IWC PORTUGUESE CHRONO with A79350 movement that I got from Mary.

The hands look weird with some stains on it and I want to replace them new hands, but I could not find any manual how to handle the A79350 movement.

I'm a total noob in watch repair and I don't know if this is over my head to replace hands on a chrono movement, so please advice me how and also if I should do so :)

Thanks!

Others will correct me If I'm wrong, but I think this is only the name they gave to the slimmest A7750 modded with correctly jewelled transfer gears.
Best bet is to look for the A7750. But you shouldn't have to be so specific, hands swapping is the same procedure whatever the movement is.

Oh and indeed chrono hands are tiny, will fly away as soon as they could, but it's not the most complicated watch repair there is, just need patience and steady hand.
If you can find some crappy watch to work on and practice hand removing, that would be best before attempting on a valuable item.

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13oots2

I would hate to try it myself and ruin a perfectly good watch, sadly I can only work with parts larger than elephant testicles.

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VMSG
6 hours ago, Glaude said:

Others will correct me If I'm wrong, but I think this is only the name they gave to the slimmest A7750 modded with correctly jewelled transfer gears.
Best bet is to look for the A7750. But you shouldn't have to be so specific, hands swapping is the same procedure whatever the movement is.

Oh and indeed chrono hands are tiny, will fly away as soon as they could, but it's not the most complicated watch repair there is, just need patience and steady hand.
If you can find some crappy watch to work on and practice hand removing, that would be best before attempting on a valuable item.

Thank you. what i'm "afraid" of is removing and returning the crown. this is why i'm looking for a guide.

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Glaude
19 minutes ago, VMSG said:

Thank you. what i'm "afraid" of is removing and returning the crown. this is why i'm looking for a guide.

Why are you afraid of that ? It's a simple stem removal.

Watch this video to see how a gen 7750 is tinkered with :) 

https://www.youtube.com/watch?v=LxXd9NpG2p0

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VMSG
3 minutes ago, Glaude said:

Why are you afraid of that ? It's a simple stem removal.

Watch this video to see how a gen 7750 is tinkered with :) 

https://www.youtube.com/watch?v=LxXd9NpG2p0

Thanks! as I said i'm a complete noob.

Valjoux 7750 equals A7750?

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Glaude

the A7750 is the Asian copy  of the Valjoux 7750

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GingerBlubba
12 minutes ago, Glaude said:

Why are you afraid of that ? It's a simple stem removal.

Watch this video to see how a gen 7750 is tinkered with :) 

https://www.youtube.com/watch?v=LxXd9NpG2p0

Oooh, nice, very therapeutic!

Have you ever tried taking apart, cleaning and putting back together the mainspring? Is it fiddly? I'm assuming you need some sort of special tool to get the spring wound up and put back in?

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VMSG
7 minutes ago, Glaude said:

the A7750 is the Asian copy  of the Valjoux 7750

When you say "copy" - can I follow a Valjoux 7750 guide? or it is "inspired" but will look completely different when I open the case?

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Luxuracer

My recommendation to you is .... DO NOT DO IT .... ! 

If you never worked on a watch movement before the chance that you will mess up that A7750 is 99.999%

Buy some cheap watch on Ebay or the Gate .... buy the correct tools ... start to play with those cheap movement before you do anything with your IWC!

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Glaude
15 minutes ago, Gingerbubba said:

Oooh, nice, very therapeutic!

Have you ever tried taking apart, cleaning and putting back together the mainspring? Is it fiddly? I'm assuming you need some sort of special tool to get the spring wound up and put back in?

Not done it yet, But there's indeed a special tools to put it back easily together, you can also do without.

Here the taking out the mainspring part : https://www.youtube.com/watch?v=DlyNICm2N9k
Here the fitting it back with a tool : https://www.youtube.com/watch?v=UrUQtVQIgQ0
Here without a tool : https://www.youtube.com/watch?v=BGzc2xWlixE

(Tool is not that expensive for once : https://www.cousinsuk.com/product/watch-bergeon-handles-for-winders)

10 minutes ago, VMSG said:

When you say "copy" - can I follow a Valjoux 7750 guide? or it is "inspired" but will look completely different when I open the case?

From what I remember yes, you could use Valjoux 7750 guide to help you, but be advised that for anything other than a hand replacement, you should start with a simpler movement than the very tedious A7750

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GingerBlubba
31 minutes ago, Glaude said:

Not done it yet, But there's indeed a special tools to put it back easily together, you can also do without.

Here the taking out the mainspring part : https://www.youtube.com/watch?v=DlyNICm2N9k
Here the fitting it back with a tool : https://www.youtube.com/watch?v=UrUQtVQIgQ0
Here without a tool : https://www.youtube.com/watch?v=BGzc2xWlixE

(Tool is not that expensive for once : https://www.cousinsuk.com/product/watch-bergeon-handles-for-winders)

It actually looks easier without the tool (though I'm sure that's just a reflection on how good the watchmaker is at doing it by hand). I seriously doubt I could get that fucker back in the barrel by hand.

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VMSG
11 hours ago, Luxuracer said:

My recommendation to you is .... DO NOT DO IT .... ! 

If you never worked on a watch movement before the chance that you will mess up that A7750 is 99.999%

Buy some cheap watch on Ebay or the Gate .... buy the correct tools ... start to play with those cheap movement before you do anything with your IWC!

Yes, I'll try it first on some cheap reps that I have.

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GenTLe
My recommendation to you is .... DO NOT DO IT .... ! 
If you never worked on a watch movement before the chance that you will mess up that A7750 is 99.999%
Buy some cheap watch on Ebay or the Gate .... buy the correct tools ... start to play with those cheap movement before you do anything with your IWC!
Totally completely agree! 7750 hands are DIFFICULT to remove and you will destroy that watch!

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VMSG
18 minutes ago, GenTLe said:
12 hours ago, Luxuracer said:
My recommendation to you is .... DO NOT DO IT .... ! 
If you never worked on a watch movement before the chance that you will mess up that A7750 is 99.999%
Buy some cheap watch on Ebay or the Gate .... buy the correct tools ... start to play with those cheap movement before you do anything with your IWC!

Totally completely agree! 7750 hands are DIFFICULT to remove and you will destroy that watch!

What makes them hard to remove? if I'll practice on another (non 7750) watch it is fine? or you think that it is still a big risk?

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tonyh7

What makes them hard to remove? if I'll practice on another (non 7750) watch it is fine? or you think that it is still a big risk?

GenTLe  knows his stuff. Respect his wisdom and don't feck with it. 

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Nikosaldente
12 minutes ago, tonyh7 said:

What makes them hard to remove? if I'll practice on another (non 7750) watch it is fine? or you think that it is still a big risk?

GenTLe  knows his stuff. Respect his wisdom and don't feck with it. 

  •  

^^^^^This!

7750 Hands sit Lower and closer to the Dial!

They are Small and delicate and even if you manage to remove them without doing any damage to the Dial, you might do some harm when you try to install the New Set of Hands!

Listen to GenTLe, he is like the Yoda of watches!

latest?cb=20150206140125

 

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VMSG
2 minutes ago, Nikosaldente said:

^^^^^This!

7750 Hands sit Lower and closer to the Dial!

They are Small and delicate and even if you manage to remove them without doing any damage to the Dial, you might do some harm when you try to install the New Set of Hands!

Listen to GenTLe, he is like the Yoda of watches!

 

 

 

I'm listening, this is why I ask - to learn :)

So what do you suggest? do nothing and live with these unperfect hands? go to a watchsmith (that i'm not sure ever handle a 7750)?

BTW, this is a new watch that I just got from Mary

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Nikosaldente

I see what you mean; There are seem to be something like stains/smudge on the Hour/Minute Hand only!

Firstly, you should have noticed that from the QC pictures!

Now that's gone......

The easiest thing to do without doing any harm is to remove the whole movement from the case and try to Clean the hands with a cotton swab dipped in Isopropyl Alcohol....

The other thing you can do is to order a new set of hands from a TD and send the watch to a Rep friendly watchsmith nearby to the job for you:D

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VMSG
18 minutes ago, Nikosaldente said:

I see what you mean; There are seem to be something like stains/smudge on the Hour/Minute Hand only!

Firstly, you should have noticed that from the QC pictures!

Now that's gone......

The easiest thing to do without doing any harm is to remove the whole movement from the case and try to Clean the hands with a cotton swab dipped in Isopropyl Alcohol....

The other thing you can do is to order a new set of hands from a TD and send the watch to a Rep friendly watchsmith nearby to the job for you:D

Thanks. regarding the QC - it depends on the lighting and Mary's QC photos I just couldn't see it. Mary said she would send me a new set of hands - and therefore this thread

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GingerBlubba
1 hour ago, VMSG said:

What makes them hard to remove? if I'll practice on another (non 7750) watch it is fine? or you think that it is still a big risk?

Whilst also advocating that OP doesn't try this repair himself, I'd also love to know the answer. Why are 7750 hands harder to remove? Are they still just friction fit? Is it still the same technique to remove it with levers it do you need the tweezer like removal tool?

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GenTLe

Ok, so:

The central chronograph second hand is well pressed on its post, so that the hand will not move when the chronograph is reset. The post is only 0.2 mm so extremely fragile.

If you don't have the right manuality to remove that hand you will end up with the hand tube separated from the hand itself. The tube will remain on the movement pinion, and it will be extremely hard to take it out without bending the pinion or squishing the tube. The tube itself will be hard to put back on the hand without damaging the hand... And a micro amount of glue will be necessary to make the tube stable when fit back on the hand.

Putting back that hand is also critical: you will need a movement holder able to support the opposite side of the gear pinion or, pressing back the hand, you will risk to damage the gear or push out the supporting jewel. The alignment to zero of the hand is not easy: you may need to take the hand out and refiit it few times before you get it resetting to 12 sharp, risking what I wrote before.

The subregister hands are also not the easiest to take out and refit: there is very little space between them and the dial, and the dial protector will not fit under them, making very easy to scratch the dial removing them. For the minutes and hours counters also it is again difficult to have them resetting in the right place.

 

Ah, on 7750 also the stem isn't the easiest to remove and refiit: the release pusher requires more force than the 2824/36 but not too much to avoid breaking something in the keyless. And insertion sometimes requires the release pusher to be pressed a bit to make it click in position (providing the stem is already inserted in the proper way: newbies often just push it without finding the right position and kill the keyless).

 

The spots of the hands in the OP's watch probably are oxidation (the gold plating sometimes is done with a mix containing a bit too much copper).

Personally I'll take the movement out, protect the dial and use a ear stick to DELICATELY try to clean them with isopropyl alcohol, AVOIDING to drip on the dial. Eventually I'll search the web for some other fluid known to be able to remove oxidation, for instance lemon juice or eventually vinegar, always applied on ear stick and passed DELICATELY on the hands without having it dripping on the dial. In this case also pass again with isopropyl after lemon treatment.

Note: the cleaning must be chemical based, not mechanical. I mean you will not press the ear stick on the hands to "brush away" the stains, it is the chemical action of the fluid on the cotton that will clean the stains.

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VMSG
10 minutes ago, GenTLe said:

Ok, so:
The central chronograph second hand is well pressed on its post, so that the hand will not move when the chronograph is reset. The post is only 0.2 mm so extremely fragile.
If you don't have the right manuality to remove that hand you will end up with the hand tube separated from the hand itself. The tube will remain on the movement pinion, and it will be extremely hard to take it out without bending the pinion or squishing the tube. The tube itself will be hard to put back on the hand without damaging the hand... And a micro amount of glue will be necessary to make the tube stable when fit back on the hand.
Putting back that hand is also critical: you will need a movement holder able to support the opposite side of the gear pinion or, pressing back the hand, you will risk to damage the gear or push out the supporting jewel. The alignment to zero of the hand is not easy: you may need to take the hand out and refiit it few times before you get it resetting to 12 sharp, risking what I wrote before.
The subregister hands are also not the easiest to take out and refit: there is very little space between them and the dial, and the dial protector will not fit under them, making very easy to scratch the dial removing them. For the minutes and hours counters also it is again difficult to have them resetting in the right place.

Ah, on 7750 also the stem isn't the easiest to remove and refiit: the release pusher requires more force than the 2824/36 but not too much to avoid breaking something in the keyless. And insertion sometimes requires the release pusher to be pressed a bit to make it click in position (providing the stem is already inserted in the proper way: newbies often just push it without finding the right position and kill the keyless).

The spots of the hands in the OP's watch probably are oxidation (the gold plating sometimes is done with a mix containing a bit too much copper).
Personally I'll take the movement out, protect the dial and use a ear stick to DELICATELY try to clean them with isopropyl alcohol, AVOIDING to drip on the dial. Eventually I'll search the web for some other fluid known to be able to remove oxidation, for instance lemon juice or eventually vinegar, always applied on ear stick and passed DELICATELY on the hands without having it dripping on the dial. In this case also pass again with isopropyl after lemon treatment.

Thank you!

giphy.gif

But even to "just" clean the hands I'll need to open the movement and you say that it is also a big risk, right? (just making sure I understand)

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GingerBlubba

Oh @GenTLe ! Thanks a lot buddy, I really appreciate you taking the time to share that. Great knowledge! I love this forum!

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Glaude
2 hours ago, Gingerbubba said:

Oh @GenTLe ! Thanks a lot buddy, I really appreciate you taking the time to share that. Great knowledge! I love this forum!

When you're in need, just call Super@GenTLe to the rescue ! :D 

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