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onzenuub

Movement review - Asian 7750 with running seconds at 6.

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onzenuub

Originally posted and created by Ziggyzumba @ RWGcc

 

Introduction

 

This A7750 however is vastly different from the rest, not only in fit/finish/cleanliness etc, but in the most important area for the purists, its a 28,800 BPH movement (8 ticks per second, identical to an ETA 7750).

 

So here is an overall view of this model, both from the dial and case back sides.

 

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Note that this particular one is from a Daytona with running seconds at 6, and if you remember my comments and review of this particular layout on a 7750 when the ETA powered one came out last year, I stated it was asking too much of the movement. In other words, adding 11 new gears to move all the sub-dials over the face, is not a good idea and is prone to problems. Given the number of ETA powered Daytonas that have crossed my bench, and my failure to correct the problems with them (as long as you dont consider freezing sub-dials is correcting the problem), I dont see how this layout will work any better given the Asian power verses the Swiss powered models. I was not to be disappointed in my findings

 

So lets have a look at this movement in detail and see what it has in store for us. First of all, the finish is far superior to the previous models (7750B, 7750B1 etc), I am not sure what to call this one, but its not in the same league as the predecessors, not even close.

 

Teardown revealed a clean movement, and very well made parts and pieces, but not a drop of oil except for in the balance cap jewels (why will be revealed, it’s not what you think, I believe not oiling the movement was a deliberate move). There is no comparison to the other Asian 7750s I have worked on, this is totally different and vastly superior.

 

Details and pictures

Here are some various detailed pictures of the parts and pieces, I did not find any dirt or metal pieces in the movement. It was very clean.

 

Balance and escape

3658352488_0341b0f9f4.jpg

 

winding gears

3658352556_e93f741039.jpg

 

auto winding bridge and pieces

3657559759_ccb99358e5.jpg

 

subdial hands gears

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new plate with the transfer gears for the subdials

3658352786_75cc19458b.jpg

 

dial side of the movement with the above bridge removed

3658352870_fa25aaefb8.jpg

 

backside of the new bridge

3657560049_92c75e9f96.jpg

 

keyless works details, note the nice finish on the bridges and parts

3657560121_18bced0303.jpg

 

I should add that the reason the movement was sent in at all, was because it did not wind in the auto mode, if you wore it, after a while it would stop working. Hand winding would let it run for 36 + hours but no automatic wind what was the problem? Well as soon as the case back came off, the rotor fell to the floor, come to find out the rotor is broken off of the bearing. This can happen, and I am simply replacing it with a new one

 

The owner decided to have the watch serviced along with the repair, and that is a good idea, at least he has a known condition of the watch when it leaves the shop and can expect 5 years before needing another service. Given the spotty history of the Asian 7750, servicing is an investment in the long run.

 

Not only is the quality of the overall movement impressive, once I tore into it in detail, it had more surprises for me.

 

If you remember my initial teardowns on these models, everyone had a few common problems, dirt, lack of oil, and a crappy cannon and 12-hour wheel. Neither the cannon or 12-hour wheels are lubricated, but even more problematic is the fact that the cannon wheel doesnt have enough friction, which shows itself by the time on the hands running behind, but the seconds being accurate. For more details on this, see my previous posts.

 

On every Asian 7750 I service, I have to put the cannon wheel on the jewel press, and compress part that holds the clutch in place to increase the friction. This is not easy and can result in some surprises, on one job, the cannon wheel disintegrated when the press slipped and touched the side of the gear ah the stories I could tell

 

Improved cannon pinion

 

The cannon pinion on this one is dry (no change there), but had as much friction as an ETA 7750, I was shocked as this has always been a big issue. Check out the quality of the clutch part of the cannon pinion, well crimped and 100% better than the old ones, so this is one big problem fixed – finally (ETA Cannon wheels are not interchangeable with the Asian ones, if they were I would not be fixing them myself

 

3657560217_2081488e91.jpg

 

Now the rest of the parts look as good as any ETA, I see no reason for any problems with regular servicing and maintenance.

 

More detailed pictures

 

Here are some various detail shots.

 

This is the mainspring barrel seat area on the motion works bridge

3657560315_a15f84a317.jpg

 

here is the mainplate with from top left to bottom right, the mainspring barrel, the 4th wheel, 3rd wheel, 2 wheel and the escape wheel

3658353272_c7206da113.jpg

 

keyless works and the hacking lever on the right side

3658353350_74a6363210.jpg

 

Close up of the gear on the mainspring barrel that drives the 12-hour counter on the dial side:

3658353418_801ac9b36b.jpg

 

Banking pins (where the pallet arm sits), much better quality than the old 7750s

3657560637_d29dcda74d.jpg

 

This is the dial side, just below the new plate for the transfer gears, this is where the minute wheel, cannon wheel sit (minute wheel goes in the large space on the left)

3657560733_3de77989cf.jpg

 

Various shots of the assembly, here is the balance in place and the basic movement assembled.

 

3658353678_043166c78b.jpg

 

This is the click wheel (clutch for the auto-winder rotor), note that its a spring ratchet and is not prone to hand-winding problems as the click wheels with the arms are (2836-2 series).

 

3658353738_6c749645e0.jpg

 

The big brass wheel is the chrono center seconds wheel, and the arm below it is the transfer gear taking running seconds from the 2nd wheel and moving it up to the chrono. On this one again we have brass on steel, so there is no wear issues

 

3657560921_f2e04b3910.jpg

 

This is the bottom chrono reset lever assembly with the reset arm, brake lever, and pusher piece. This spring is very difficult to install. All this is for the 12 hour counter.

3658353928_78360850bb.jpg

 

Overall view so you can see the relationship of the various parts

3658354036_058cc245ba.jpg

 

Here is the 11 new gears in place before the last bridge is installed, just so you can see how complex this addition is to the basic movement

3658354146_6ebff8343c.jpg

 

Heres another big surprise, this arrow is the 30 minute timer centering spring eccentric screw adjustment, its actually a screw and can be adjusted. On the previous versions, its a backwards screw and is not adjustable. When I see attention to these fine details, it convinces me that someone put some real effort and thought into getting this one right

3658354224_687bd75319.jpg

 

Now the post you see here is the centre post for the chrono seconds wheel. If you never took notice, every gear in the movement is brass on steel, there is a good reason for this, and it all comes down to friction. On the ETA 7750, this tube is steel, but on this one, someone decided it was better to have it in brass.

3657561359_c09956d3fd.jpg

 

Even more amazing, is that they installed a jewel on the other end where the shaft comes out and the seconds hand attaches. Now this is impressive, ETA does not do this, but someone has made every effort to reduce friction, and increase the life of the movement

3657561411_589cbc3412.jpg

 

More improvements, note the mainspring barrel, on the ETA and the older Asian models, the barrel is split in the middle. This one is a cap type, much better design in my opinion. Nice long mainspring, smooth barrel sides which is common on the 7750. It was clean, only dry, so I lubricated the sides of the barrel with special high friction grease, and installed the spring and lubricated it with oil.

3657561519_902974301f.jpg

 

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Here is the balance cap jewels, they were the only ones with oil, this is what they looked like before servicing.

3657561683_cca0b201df.jpg

 

Balance close up

3658354752_a3e02ab88b.jpg

 

Now this is a new running seconds at 6 model, and as such is going to suffer from the same problems as the Swiss powered one, namely asking too much from the movement by having to power all these new gears, if you remember the review last summer, the transfer of all the sub-dials requires 11 (yes Eleven) new gears.

 

Transfer gears are a problem

 

You can see here the new gear on the running seconds, this will mate to 5 more gears before the seconds can be displayed at 6 - can you say loading down the movement remember this is a constant load, as long as the watch runs, this load is applied to the basic movement.

 

1 is the cannon gear, 2 is the new gear for the transfer of running seconds (this is the shaft at the 9 sub-dial position on the movement, the 2nd wheel which is running seconds), and 3 is the minute wheel, 4 is the hour wheel what the hour hand goes onto

3657561849_0abb314ddc.jpg

 

I put the movement on the watch analyzer Before installing any transfer gears and adjusted the beat and rate. Heres what it looked like

3657561945_5896fbd02d.jpg

 

3657562011_953b23f30d.jpg

 

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3657562237_e5c7b62fda.jpg

 

3658355210_1c41092475.jpg

 

Then I put the bridge over the dial side and re-tested the timing and beat. This is with only 1 of the transfer gears in place. It was a mess, there is such a high load from the one gear you see here, that the watch finally stopped working altogether. That is with only one gear in place, imagine installing the next three.

 

3657562373_082b39f849.jpg

 

So I tried to fix the problem, if indeed it can be fixed, remember this is a design problem, not a servicing one After 4 disassemblies of this bridge and gears, oil, no oil, clean, re-oil, etc, I finally pressed the transfer gear off the plate by pushing the center pin out with my jewel press, and cleaned it really well and applied minimum oil on the slider part. Reassembled and it worked finally.

 

This is the first gear I am talking about, if you note the gear under the plate gold coloured, its the one on the end of the second wheel. It mates to the first of the 5 transfer gears which you see under the plate - its silver coloured. This is the one that had the problems, and the pin in the center of it is what I removed and reinstalled to get it cleaned up

 

3658355368_5d012a65ac.jpg

 

I put the movement on the watch analyzer and re adjusted the beat and rate (the load changed them both), but the change was nowhere near what it was the first time with all the extra friction. So far it seems to have corrected the problem, all the gears were installed, and the movement has been running for 2 days. How it will perform in the long run is beyond me, but the Swiss ones are not doing that well (the ones I have seen anyway). It works, but just barely, the load is too great from these extra gears.

 

I did speak with the owner and he decided to remove the running seconds gears, and freeze the sub-dial as this will improve the functioning of the watch and the reliability. I think this was a good decision.

 

Anyone who has asked my opinion on a Daytona model has gotten the same answer; dont get one with running seconds at 6, everyone I have seen is problematic, its asking too much for the movement to deal with the extra load of 11 gears. The lowly movement was not designed to take this load, its like taking a 4 cylinder car engine and putting it in a large dump truck, it will work, but the engine will fail eventually sooner than later

 

Now this is only my opinion, based on what I see.

 

Why did they not oil the movement?

 

Remember I said that the movement was not oiled? Why would someone make such a nice movement, and not oil it except for the balance cap jewels? What does oil do in the pivots and jewels? Sure it reduces wear by allowing the pivot to rotate on a film of oil and not touch the jewel. It also adds a small amount of friction to the pivots - a very small amount mind you - but friction is increased when you oil a watch. A dry pivot on a jewel will require less power to turn than one with a film of oil between the pivot and the jewel, at least in the initial stages of the usage of the watch. It is possible to over-oil a movement, so much so that it doesnt run at all what is my point with all this?

 

Have you figured out yet why they did not oil the movement?

 

Take a movement, add 11 extra gears, causing the movement to be on the verge of not working, and to make it all work, reduce the friction in the movement to the least amount you can. How ? by not oiling any of the pivots make sense doesnt it, it does to me this is pure speculation on my part, but the only reason I can come up with.

 

Taking the extra 11 gears out of the picture, you have an excellent copy of a 7750, no question a vast improvement over the existing ones. I wish I could buy a dozen of these and replace the ones in my watches.

 

Even better is the fact that this movement is running at 28,800 BPH, so the seconds chrono hand is nice and smooth, identical to the OEM model.

 

If this was my watch, I would just take the running seconds gears out of the watch, freeze the 6-counter, and use the watch like this. Reason I say this is simple, the addition of these 5 gears for the running seconds, is too much for the movement to handle. I cant correct design problems, and with the running seconds in place and loading down the movement, there is no question that the watch is going to have problems, and probably stop intermittently and maybe stop running at all. I rather have a reliable watch than a non reliable one, even if it means loosing a function.

 

Summary

 

Overhaul was straight forward, only snag was the fact that once I oiled the watch, (correctly I might add not over oiled) the limit of the available power from the movement was noticeable. As soon as I added the last bridge with the extra gear, the movement came to a grinding halt. So I ended up spending a couple of hours on the extra transfer gears, and finally took the pressed gears off, cleaned them really well, and oiled with my lightest oil and reassembled. Then I took extra care to make sure the pins were pressed just right so there was as little clearance as possible and as little friction as well. My efforts were rewarded since the movement will now run with all the gears in place but I have my doubts that it will be reliable in the long run.

 

Of course, one could always assemble the watch with no oil at all, as it was delivered, but this is not a solution. It is going to fail even quicker if its not oiled, I cant in good conscience send a watch back after servicing it not oiled, all movements need oil to run correctly, otherwise pivots are going to wear out and the watch will stop running.

 

So this confirms the fact that the reason the ETA 7750 was chosen in the first place to power the new running seconds at 6 Daytona, was because of the available power from the ETA. This is a good effort to accomplish the same thing with an Asian model, but I think it will not work in the long run. If they did not oil the movements on purpose, then they will wear out over time(consider that this is only one sample I have looked at, but normally what I see on one, I see the same thing on the others, same with the Original Asian 7750, experience has shown that they are mostly dirty and not oiled). Also consider that this is only my analysis on what I think based on my experiences, I could be way off base (well not on the no-oil = worn out movement, that is correct).

 

Conclusions

 

Question is, was this movement developed specifically for the Daytona, and is this why the quality is on par with an ETA 7750? Or is this the new standard of Asian 7750s we can expect to see. My Omega BA is not equipped with this version of the 7750, and so far this is the only one I have seen.

 

How widespread is this movement, I don't know, for the record this watch is from Andrew.

 

Many questions answered, some more not answered but I think this and the new 6497-2 are the way of the future, 2006 is only 3 weeks old, and already things are looking up

 

Now if these were available in the 7750 and 7753 layout, and you could source the movement alone, I would be the first to buy them, service them, and install them in place of my existing Asian 7750's.

 

Thanks for reading my thoughts and comments.

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greg_r

Gotta be a sticky. Thanks, Onze!

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RolexAddict

This is a very informative rewiew, especially if Ziggyzumba wrote A7750 reviews will all different sub-dials configuration.

 

I just want to precise, 1 year ago, before the rebuilt of this forum, I started already to disassemble the new 28800bph A7750 sec. at 6 and claimed its a good movement and all was said before was just obsolete bad infos applied on this new movement by ignorance

O.k, I am just an amateur :thumbsup2:

 

Onze, this is a good find :thumbsup2: what is following is not to criticise you, just what I think :

 

This forum cannot have the same credibility like the others if we continue to copy and paste the productivity of other people.

 

That's why I don't want to see what I wrote on other boards. If I was Ziggyzumba, I would forbid this practice

 

We need a little more ideas and creativity from members here

 

I am sure Onze's reaction will be to post a pic with a pussy or a dick :lol:

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greg_r

RA, I get where you're coming from, but we're a young board and don't have the wealth of background info and reference materials that you'll find on the other boards. I think these reposts serve a useful purpose as we continue to grow. A lot of this kinda stuff gets cross-posted across all of the boards anyhow.

 

For sure, though, what we need is more original content. And boobies. :lol:

 

:thumbsup2:

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onzenuub
This is a very informative rewiew, especially if Ziggyzumba wrote A7750 reviews will all different sub-dials configuration.

 

I just want to precise, 1 year ago, before the rebuilt of this forum, I started already to disassemble the new 28800bph A7750 sec. at 6 and claimed its a good movement and all was said before was just obsolete bad infos applied on this new movement by ignorance

O.k, I am just an amateur :thumbsup2:

 

Onze, this is a good find :rolleyes: what is following is not to criticise you, just what I think :

 

This forum cannot have the same credibility like the others if we continue to copy and paste the productivity of other people.

 

That's why I don't want to see what I wrote on other boards. If I was Ziggyzumba, I would forbid this practice

 

We need a little more ideas and creativity from members here

 

I am sure Onze's reaction will be to post a pic with a pussy or a dick :lol:

 

 

I didn't knew you are interested in dicks RA ?????? :thumbsup2: All this is done with the permisson from Ziggy, like he said in his pm: "Not a problem, if you credit me as the creator of the post, it could help others avoid a mistake."

Why would we invent the wheel when some one else invented it allready.

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WatchMe007

This was a fascinating read.

 

So there is no "clone" movement of the gen Daytona movement that is available to build a reliable Daytona rep?

 

I have a really nice Daytona rep with the seconds at 6. It is so accurate...visually...that I almost forgive the fact that it CLEARLY LOSES TIME in the order of minutes a day unless wound tight. Pre-winding a LOT makes it perfectly fine for wear, but now that I understand how the movement works it makes perfect sense. I am bummed.

 

It is the watch that lured me into the world of watches in the first place. Holy Grail of watches.

 

Can't someone come up with a solution? There is a small pile of money to be made here. A truly reliable Daytona rep has got to be worth $500 or more to more than just myself.

 

What does the movement in the original look like?

 

Are there pre-2000 Daytona reps out there with the seconds running at 9 that are more reliable and a better "super rep" solution?

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dudermania

Gentlemen - to the OP's original conclusion on these improved 7750 movements. Has anyone bought a 7750 chrono in the past year? Whats the life like? Have you had it serviced properly? I know there are a couple of folks around here that people have referred to who can service movements.

 

Damn these dealers with their 'improved 7750s' and 'clone movement' advertising!! I can't resist.

 

Top of my list is an IWC Portugese Chrono and a Tag Heuer Day Date Chrono. Talk me out of it please..OR I need a push from someone to say go on...buy one.

 

I refer to another sticky I read somewhere where as long as you don't mess with it - they last a while. I won't give the chrono itself any hassle, but can a watch with a 7750 movement (with secs@6) be used as a regular timepiece without much issue?

Edited by dudermania

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plankton

Gentlemen - to the OP's original conclusion on these improved 7750 movements. Has anyone bought a 7750 chrono in the past year? Whats the life like? Have you had it serviced properly? I know there are a couple of folks around here that people have referred to who can service movements.

 

Damn these dealers with their 'improved 7750s' and 'clone movement' advertising!! I can't resist.

 

Top of my list is an IWC Portugese Chrono and a Tag Heuer Day Date Chrono. Talk me out of it please..OR I need a push from someone to say go on...buy one.

 

I refer to another sticky I read somewhere where as long as you don't mess with it - they last a while. I won't give the chrono itself any hassle, but can a watch with a 7750 movement (with secs@6) be used as a regular timepiece without much issue?

My question as well-- if someone has the answer please PM me.

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SSTEEL

I received a sec@6 Daytona today, its a few years old, and still running strong :)

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Haltec

Beautiful article. Loving B-200 Vibrograf

 

 

Br

 

 

Haltec

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Jeanmarc

Thanks a lot for reporting that study, it helps me a lot, specially to remove the fault gear, Now after 3 years I got my Daytona 116509 working again. (freeze second sub dial)

.

Thanks, Thanks, Many thanks to Ziggy.

 

J-M

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