How do you re-seat the stepper motor rotor

[OS1111]

Hi,

I’m very new to quartz watch repair and renovation, so please bear with me. I have bought several spares & repairs Seikos from eBay and am taking them apart, cleaning and reconstructing them. I have bought quite a lot of tools but realise I’ll need more. 

The first issue I have is how on earth do you reseat the stepper motor rotor when the magnet causes it to keep jumping to any piece of magnetic material it can. The train bridge sits on top of the train, which is moderately easy to reseat but fitting the rotor under the same bridge I cannot figure out.

Can anyone advise?

Thanks,

[jdm]

Can you post a pic of the area where the rotor seats?

The other day I took apart a Polijot and clearly it had one side space with an hole for the purpose of fitting a small jig, probably plastic made.

A way would be, is guess, a small about of rodico that you can cleanly remove from around the rotor.

There is a book which is only about quartz repair, I am sure someone will fill with its title.

Edited August 19, 2020 by jdm

[Ishima]

Generally speaking this is one of the harder parts of quartz watch assembly. 

You may find it helpful to use non steel tweezers for the stepping motor (brass, normally)

Sometimes you can just get them in place with a bit of precision and persistence. Other times your problems are exacerbated by a lose 'stator' the magnetic plate surrounding the stepping motor. and you may need to secure it somehow during the assembly, until everything's back in place and the stator is secured by the rest of the parts. 

Sometimes you're better off putting on the gear train bridge with the screws not screwed down fully, but in place and trying to get everything to slip into place with a little bit of gentle downward pressure on the bridge, before tightening the screws. 
 

Edited August 19, 2020 by Ishima

[watchweasol]

Hi      https://watchfix.info/   This link give you a guide.    repairing quartz watches   by Henry B  Fried an old book but contains usefull information  or mechanical and quartz watch repair by Mike Watters,   the quartz watch repair manual  Louis  A Zannoni are but a few    for your intest      The attached manual covers both Quartz and Mechnical.

Witschi Training Course.pdf

[rodabod]

The rotor will often sit at an angle, but you just need I make sure that the lower pivot is seated before placing the bridge on above. 
 

I use No. 5 Dumont in Dumostar steel for moving the pivots into position. 

[HectorLooi]

Yes, it's an extremely fiddly task. Putting on the upper plate and trying to nudge the pivots into their holes is not a good idea, especially if you have plastic pivots. If the plastic pivots get bent just a little bit, the movement becomes useless. 

I learnt an ridiculously simple trick from my mentor. Just put a piece of iron under the bottom plate and the rotor will be attracted to it and stay in its hole on the bottom. If you have a loose stator that sticks to the rotor, instead of iron, stick a small magnet under the plate to pull everything down. It works. Try it.

[jdm]

13 hours ago, HectorLooi said:

Yes, it's an extremely fiddly task.

One thing is fiddly, another is next to impossible. The factory assembles hundreds of modules per hour, the question is how they do that? 

Quote

Just put a piece of iron under the bottom plate and the rotor will be attracted to it and stay in its hole on the bottom.

Maybe they do that or have special jigs.

Edited August 20, 2020 by jdm

[HectorLooi]

1 hour ago, jdm said:

One thing is fiddly, another is next to impossible. The factory assembles hundreds of modules per hour, the question is how they do that? 

Maybe they do that or have special jigs.

I'm still waiting for someone who works in a watch assembly plant to let the cat out of the bag. 

[Johndub]

Did it myself for the first time last week. Brass tweezers were vital, and placing a screw on the other side of the plate to keep the rotor in place helped hugely. 

Spent several hours without these two tips, still took a little while even with them, but got it done. 

[OS1111]

Wow! So many ideas, thanks for all of them. My next purchase is going to be some brass tweezers, followed by some more padding for the cell!

I like the idea of using metal or a magnet under the movement, I’ll definitely give that a try.

Tried securing the bridge and broke the top off the centre cog! Fortunately I have another :-) 

How would you get the rodico back out of the motor once the bridge is back in place.

I also wonder how they do this on a production line. How do they get the bridge down on the pivots when the train is loose? And then to get a stator in as well when it would much rather ping off sideways to the magnet surrounding it?! 

I watched a video on YouTube where the guy recommended taking the circuit board and coil out and dunking the entire watch in spirit! So I thought in for a penny, took the electrics out off a watch, immersed the entire watch in to some quartz watch movement cleaner and in to the sonic cleaner. Blow me down if the watch didn’t burst into life. One downside is that only the non face side gets lubricated after cleaning. Any thoughts on how extreme cleaning should get would be most welcome.

[Nucejoe]

Some assembly lines are fully robotic, I think Ronda is. The entire line is like 7meters long, thats how swiss can compete with others.

Beleive it or not, I put a drop of avgas on pivots and grab any gear I have access to and turn just a bit, then drop the whole movement in avgas with battery in as its it running, let it run for a min or so, take out dry with puffer, repeat in twenty mins, running all the time, submerged in fluid or out. then oil a little. done. but thats in case if cheap movements.

Currently have fully dismantelled a Ronda, clean holes, brush with avgas, oil, much like a mechanical movement. usually runs for several year, much depends on oil.

[OS1111]

Hi @Nucejoe,

By avgas do you mean aviation fuel?!

[OS1111]

Brass tweezers arrived today. As you all said, much easier to handle magnetic parts with. About 20 minutes later I have the train back under its bridge and working. Next challenge is to repeat the task! Going to try with a magnet under the watch to try and keep all the  magnetic parts down.

[HectorLooi]

Good show!

Now for a greater challenge, do a few Ladies quartz movements. 

[OS1111]

I've barely started! Next you'll be asking me to make my own cogs! Mind you I did accidentally buy a movement holder for tiny watches so that's a start :-)

[VWatchie]

Already mentioned but illustrated in this post. Search the linked page for "little trick that will cure this".

[Nucejoe]

On 8/24/2020 at 3:09 PM, OS1111 said:

Hi @Nucejoe,

By avgas do you mean aviation fuel?!

Sorry for late response, yes,   avgas= aviation gas. won't hurt the coil wire coat.

[OS1111]

 

9 minutes ago, Nucejoe said:

Sorry for late response, yes,   avgas= aviation gas. won't hurt the coil wire coat.

Not widely available in the UK!

[OS1111]

1 hour ago, VWatchie said:

Already mentioned but illustrated in this post. Search the linked page for "little trick that will cure this".

Wow! brilliant link @VWatchie I also decided to use moebius quartz oil but not entirely clear on what ghost oiling is nor how to achieve it. I've just based my oiling on the Seiko service manuals which is like traditional watch oiling. Not sure why the screw needs demagnetising? I have loads of tiny screws lying around that would do but surely the magnetism produced by the stator would vastly exceed any transferred to the screw in the time taken to reassemble the train and bridge?

[OS1111]

On 8/19/2020 at 9:14 PM, watchweasol said:

Hi      https://watchfix.info/   This link give you a guide.    repairing quartz watches   by Henry B  Fried an old book but contains usefull information  or mechanical and quartz watch repair by Mike Watters,   the quartz watch repair manual  Louis  A Zannoni are but a few    for your intest      The attached manual covers both Quartz and Mechnical.

Witschi Training Course.pdf 4.65 MB · 7 downloads

Thanks for the link @watchweasol

[VWatchie]

2 hours ago, OS1111 said:

Wow! brilliant link @VWatchie I also decided to use moebius quartz oil but not entirely clear on what ghost oiling is nor how to achieve it. I've just based my oiling on the Seiko service manuals which is like traditional watch oiling. Not sure why the screw needs demagnetising? I have loads of tiny screws lying around that would do but surely the magnetism produced by the stator would vastly exceed any transferred to the screw in the time taken to reassemble the train and bridge?

Thanks @OS1111! I really don't think you need to worry about the magnetism. I simply think that the author of the walk-through @Lawson is a bit of a "purist", you know, no magnetism anywhere 

Anyway, perhaps you'd find my ETA Calibre 955.112 Service Walkthrough useful where I've included lubrication suggestions!?

 

[OS1111]

Thanks again @VWatchie