Is this 7750 movement f*cked?

[the_faz_man 0]

Hi all,

 

I recently received an IWC Top Gun 3380-03 from a TD. For the first day or two the movement was temperamental (stopping frequently even though fully wound), and now it has stopped working altogether. It has as an Asian 7750 movement.

 

I opened the case back and noticed two loose screws. In the photo below you can easily see one of the screws, but the other one was obstructing the balance wheel (a bit harder to see in the photo). Using teeny-tiny tweezers I was able to remove the screw obstructing the balance wheel. But when I did this the watch hands started spinning at great speed as if I was in a time warp. WTF?

 

 

Can anyone shed any light on where these two screws are supposed to be, and why the hell the watch now goes super-speed?

 

I think I am going to have to return the watch to the TD for repair, however I would like to avoid that if possible.

 

Any thoughts would be appreciated.

[Dendo 93]

Could be movement holder screws that have come loose or extras dropped into the movement.

 

Can you wind it now or not? If not - maybe you damaged the watch removing them, and the mainspring has unwound.

[the_faz_man 0]

Could be movement holder screws that have come loose or extras dropped into the movement.

 

Can you wind it now or not? If not - maybe you damaged the watch removing them, and the mainspring has unwound.

Yeah, it definitely still winds (both manually and via rotor). As stated in my original post, after I dislodged the screw obstructing the balance wheel, the watch hands turn at an amazing pace, around 1 hour per second.

[the_faz_man 0]

On closer inspection I can see that the two loose screws (Half-head) are the ones that hold the movement to the case.

 

But I am still hoping that someone can help me with why the movement is now running at monumentally fast speed (1 hour per second)? I was very careful when I removed the lodged screw, but did I bump some sort of regulator part? (Please note that I am a noob when it comes to movement parts).

[rawbaws 91]

I'm the last person you should ask about movements but I highly doubt you could regulate a watch to be that fast. Something much much worse happening here!!

[GenTLe 1,509]

What do you mean 1h per second? If it goes THAT fast it means that the minute hand does a complete circle in 1 second... The only way something like that can happen is that the pallet fork broke and it is not stopping the escapement wheel to freely rotate. And the balance wheel in such circumstance is not pushed and so it doesn't move (unless manually touched).

And the watch should stop running within 30 secs or so, due to the complete discharge of the mainspring.

[fellowsis 1]

I havery a similar issue with the top gun I bought about a year ago, but also the date and day quick change no longer works and hand winding the thing feels closer to breaking every time.

Its a real shame that the one movement manufacturers use (the 7750) is pretty much readily available on our chronograph high end reps, but whether through fault in design or manufacture (another debate) these 7750's are ridiculously temperamental. I also have a carrera and skyland avenger with one in and they hAve no issues ��

Edited August 3, 2016 by fellowsis

[the_faz_man 0]

What do you mean 1h per second? If it goes THAT fast it means that the minute hand does a complete circle in 1 second... The only way something like that can happen is that the pallet fork broke and it is not stopping the escapement wheel to freely rotate. And the balance wheel in such circumstance is not pushed and so it doesn't move (unless manually touched).

And the watch should stop running within 30 secs or so, due to the complete discharge of the mainspring.

 

You are correct, it is discharging the fully wound spring in about 30 seconds!! Hmmmm sounds like it is all buggered up so will need to return it to the TD

[GenTLe 1,509]

Looks like! :(

[Gazzla 23]

QC coming out of the factories is getting worse.

[the_faz_man 0]

Yeah, dissapointing....my first rep with a 7750, and perhaps my last!! Now to decide whether to risk sending it back to China or to sell it to someone who might be able to fix it.

[GenTLe 1,509]

If it's just the pallet fork, then the repair consists in removing the rotor, then the minute gear spring, then remove the balance and its bridge, and finally remove the pallet fork bridge and check what's going on there. Like 4 screws in total.

BUT...

it may be that the problem is also on the escapement wheel, or that the pallet fork is fine and the problem is that the balance lost its impact jewel, or that the pallet fork lost the stones and they are floating inside the movement and it needs to be fully opened...

 

Not an easy decision in theory... But being it a sec@6 then I'd send it back to the factory because:

1) few people will put their hands in it

2) if something get broken, there are nearly no spare parts, especially for these new jeweled transfer gear ones

 

[NCRich 13,764]

One of the big reasons I don't buy chronos. Plus my eyes are so bad I can' see the dials.

[BadPickle 2,749]

QC coming out of the factories is getting worse.

 

 

A little unfair methinks, this could have happened at any point during its several thousand mile journey, them delivery dudes don't give a shit

 

One of the big reasons I don't buy chronos. Plus my eyes are so bad I can' see the dials.

 

 

+1 gazillion

[Abe Fromen 1,623]

One of the big reasons I don't buy chronos. Plus my eyes are so bad I can' see the dials.

 

This as well.

[TRANSPORTER 1]

I'm agreeing with genTle aswell, im abit late to the party but that is exactly what I would of diagnosed the problem as, then I would be having the balance out to confirm my suspicions

[FunnyStarSystem 7,538]

Sorry to hear this faz. I was admiring your pick up while awaiting my spitfire chrono, which has I believe the exact same 7750 movement (they look identical at least), and a completely different set of problems! The one similarity is they both seem to have come in without the movement clips secured. The factory QC is abysmal.

 

Good luck with yours, sounds like it's going to need serious work, you could always check with Katt and see if he can fix it, sending back to China is always a multifaceted risk.

 

If you don't mind, I'm going to describe my movement's problems here instead of starting a new thread, see if the same guys who sleuthed yours can do the same for mine.

 

When fully wound the watch works fine, keeps accurate time, and the chrono works and resets perfectly. But wear it to sleep or put it away and allow the spring to run down a bit, and the hands (hour and minute) inevitably get stuck, always at X:44, while the seconds continue to run. Pulling out the crown and moving it back and forth over the :44 where it gets stuck reveals no noticeable friction or hand touching hand. Power it back up fully and it doesn't stick at that point.

 

So a couple questions; Is this possibly damaging the movement, to have the hour and minute hands stuck while the seconds keep running? Does this sound like a cannon pinion issue or one simply of friction too minute to notice? Has anyone experienced this before whether this movement or not? I have searched around but can't find the exact same problem discussed on here.

 

Thanks for any advice

[the_faz_man 0]

Hi Inkoumori, is your watch from the ZF Factory too?

[FunnyStarSystem 7,538]

I'm not sure of the factory, this is the product page though. I'm positive someone here knows, I just can't find the discussion thread anymore; http://www.pf-818.com/-p-18989.html

 

Sometimes you have to click the link, come back and then click again to get it to work.

 

Have you decided what to do with yours?

[GenTLe 1,509]

Hey Inkoumori: yes what you wrote is entirely possible: just think about no-hacking movements like the Miyota 8215 and such: when you pull the crown to regulate the time you are moving the hr and min hands independently from the seconds that continues to run.

You can imagine your situation like if someone is changing the time backward in an extremely slow way.

 

Most probably the problem is somewhere between the driver canon pinion, the gear in the low left part of the next pic, and the intermediate set wheel, the gear partially covered by the setting lever jumper plate. Being the problem related to minute hand position at 44 mins, most probably there is some mishape in one of the gear teeth that transfer the motion to the free cannon pinion (the minute hand pinion), or some bit of hard dust.

The problem is that to arrive there hands have to be taken away, and so the date change mechanism and the calendar plate. And this is a sec@6 which makes all more difficult...

[markeym3 2]

do you have a photo after removal of the screws ...

[JSJ 0]

I would so like to get inside one of these new transfer modules to see what they look like. I'll post a WTB.

[FunnyStarSystem 7,538]

Hey Inkoumori: yes what you wrote is entirely possible: just think about no-hacking movements like the Miyota 8215 and such: when you pull the crown to regulate the time you are moving the hr and min hands independently from the seconds that continues to run.

You can imagine your situation like if someone is changing the time backward in an extremely slow way.

 

Most probably the problem is somewhere between the driver canon pinion, the gear in the low left part of the next pic, and the intermediate set wheel, the gear partially covered by the setting lever jumper plate. Being the problem related to minute hand position at 44 mins, most probably there is some mishape in one of the gear teeth that transfer the motion to the free cannon pinion (the minute hand pinion), or some bit of hard dust.

The problem is that to arrive there hands have to be taken away, and so the date change mechanism and the calendar plate. And this is a sec@6 which makes all more difficult...

 

Thanks for the reply GenTLe. Makes perfect sense, but I'm really not sure what's going on with this one now since I put it away and am letting it run down. It's been 24 hours since it repeatedly snagged on X:44, so perhaps it was a foreign object that dislodged itself or some other anomaly. It will probably manifest itself from time to time just to remind me it's a ticking time-bomb, but until then I can't really send it back and can't justify sending it out for an expensive repair. I will reopen the back and bellows it a bit, but having done that before, nothing fell out or presented itself.

 

I saw your WTB thread JSJ, if this thing explodes anytime soon I'll make you a deal! It came in, like faz's, with the movement completely unsecured, so I removed it and found no screws or clips anywhere. Whatever factory did this one didn't bother to even install them, probably better off considering what happened to faz's.

 

I will update on here next time it does something odd.

[JSJ 0]

Hey Inkoumori: yes what you wrote is entirely possible: just think about no-hacking movements like the Miyota 8215 and such: when you pull the crown to regulate the time you are moving the hr and min hands independently from the seconds that continues to run.

You can imagine your situation like if someone is changing the time backward in an extremely slow way.

 

Most probably the problem is somewhere between the driver canon pinion, the gear in the low left part of the next pic, and the intermediate set wheel, the gear partially covered by the setting lever jumper plate. Being the problem related to minute hand position at 44 mins, most probably there is some mishape in one of the gear teeth that transfer the motion to the free cannon pinion (the minute hand pinion), or some bit of hard dust.

The problem is that to arrive there hands have to be taken away, and so the date change mechanism and the calendar plate. And this is a sec@6 which makes all more difficult...

 

Thanks for the reply GenTLe. Makes perfect sense, but I'm really not sure what's going on with this one now since I put it away and am letting it run down. It's been 24 hours since it repeatedly snagged on X:44, so perhaps it was a foreign object that dislodged itself or some other anomaly. It will probably manifest itself from time to time just to remind me it's a ticking time-bomb, but until then I can't really send it back and can't justify sending it out for an expensive repair. I will reopen the back and bellows it a bit, but having done that before, nothing fell out or presented itself.

 

I saw your WTB thread JSJ, if this thing explodes anytime soon I'll make you a deal! It came in, like faz's, with the movement completely unsecured, so I removed it and found no screws or clips anywhere. Whatever factory did this one didn't bother to even install them, probably better off considering what happened to faz's.

 

I will update on here next time it does something odd.

OK cool. I'm not desperate but if you give up with it I'd be interested. I hope it keeps going for you. They are great watches.

[the_faz_man 0]

Hi Inkoumori, I ended up sending the watch back to the TD....fingers crossed!!