Quartz citizen 7920E re-assembly

[goose]

hello guys, I'm trying to re-assemble a citizen 7920E movement after a clean due to a leaking battery. i found a service sheet which i can mostly understand with a fair bit of trial and error :). The problem I have is I cant get the rotor to line up when I am putting the train bridge on. The rest of the wheels are ok and not too difficult but the rotor !!!

Can some-one enlighten me of ways to line up the magnetic rotor?

All my best, rob

[Kalanag]

Some people had success by putting a strong magnet underneath the main plate.

The problem was discussed also in the this thread (July 28 ff):

 

Edited July 9, 2022 by Kalanag

[Neverenoughwatches]

2 hours ago, goose said:

hello guys, I'm trying to re-assemble a citizen 7920E movement after a clean due to a leaking battery. i found a service sheet which i can mostly understand with a fair bit of trial and error :). The problem I have is I cant get the rotor to line up when I am putting the train bridge on. The rest of the wheels are ok and not too difficult but the rotor !!!

Can some-one enlighten me of ways to line up the magnetic rotor?

All my best, rob

Hiya Goose. Yes kalanag is quite correct. The rotor is a little shit and behaves extremely badly and should be sent to it naughty corner. Haha. I can confirm that you will need a strong magnet under the mainplate directly under the rotor. Generally it makes the rotor stand up straight to attention and if the magnet is large enought to cover the area of the other train wheels all those join in the parade as well. Ideally greg a Neo button magnet. (Neodymium ) works very well. Get 2 they are great fun.  2 of these 12mm magnets held together by their opposite poles are quite difficult to seperate by hand. Hilarious watching the missus try to seperate them  

Edited July 9, 2022 by Neverenoughwatches
Half asleep

[HectorLooi]

The magnet doesn't need to be very strong. I made a movement rest for assembling quartz movements with a small whiteboard magnet and a couple of ice lolly sticks.

The magnet holds down the coil and the rotor and stops them from misbehaving. 

[Shane]

4 hours ago, goose said:

re-assemble a citizen

 

3 hours ago, Kalanag said:

putting a strong magnet underneath

 

2 hours ago, Neverenoughwatches said:

Yes kalanag is quite correct

 

1 hour ago, HectorLooi said:

doesn't need to be very strong

Thanks guys!

I didn't know that I was going to learn something before coffee this morning but...

I've gone through several quartz movements and this looks like it might help.

Has anyone had any unwanted effects of unintentionally magnetizing other parts that now can no longer be safely degaussed.

Without an escapement I would hope the effects would be quite manageable.

Shane

[HectorLooi]

As long as the rotor is able to rotate freely, it is quite safe to use a demagnetizer on the movement. After all, that's how a line free tool works.

[Neverenoughwatches]

24 minutes ago, Shane said:

 

 

 

Thanks guys!

I didn't know that I was going to learn something before coffee this morning but...

I've gone through several quartz movements and this looks like it might help.

Has anyone had any unwanted effects of unintentionally magnetizing other parts that now can no longer be safely degaussed.

Without an escapement I would hope the effects would be quite manageable.

Shane

Not so sure that the effects would be any different from the magnetism that is produced by the watch to keep its time. Battery + quartz crystal + cmos + regulation + circuit board + coil = one second (but not always one second, can vary if no second hand on dial ) magnetic pulse. Demagnetise if you feel necessary just not with the circuit board on. I’ve tried to demagnetise a rotor, it just laughed at me. 

Edited July 9, 2022 by Neverenoughwatches

[Shane]

19 minutes ago, HectorLooi said:

As long as the rotor is able to rotate freely, it is quite safe to use a demagnetizer on the movement. After all, that's how a line free tool works.

Not sure what a line free tool is.  I will need to look into that.

Before I do this to something I care about, I will first need to give this a try on something cheap and unloved.

 

10 minutes ago, Neverenoughwatches said:

Not so sure that the effects would be any different from the magnetism that is produced by the watch to keep its time

Neither do I.  That is why I asked.

I'll give this assembly tip a try next time I work on a quartz movement.

Thanks again.

[Neverenoughwatches]

17 minutes ago, Shane said:

Not sure what a line free tool is.  I will need to look into that.

Before I do this to something I care about, I will first need to give this a try on something cheap and unloved.

 

Neither do I.  That is why I asked.

I'll give this assembly tip a try next time I work on a quartz movement.

Thanks again.

I have used this method a few times with a particularly stubborn rotor. With no problems. You can always demagnetise the movement once the train bridge is fitted. The rotor does not give up its magnetism, the movement will return back to its pre magnet use state.

2 hours ago, HectorLooi said:

The magnet doesn't need to be very strong. I made a movement rest for assembling quartz movements with a small whiteboard magnet and a couple of ice lolly sticks.

The magnet holds down the coil and the rotor and stops them from misbehaving. 

Handy little set up Hector, i love our ingenuity  . Also comes in handy when repairing Richard Keil' s teeth  

Edited July 9, 2022 by Neverenoughwatches

[Shane]

1 hour ago, Shane said:

Before I do this to something I care about, I will first need to give this a try on something cheap and unloved.

This was said in regards to demagnetizing the movement afterwards.

 

2 hours ago, HectorLooi said:

line free tool

I did not find a "line free" tool but I did find "turbo" tools.  At first (if these tools are similar) I thought you might be right in saying they would exert similar forces on the watch as a demagnetizer would.

But.. now I don't think so.  A demagnetizer works by drawing the sample through an alternating/sinusoidal magnetic field, from a higher influence to a minimal influence, disturbing/neutralizing the interal molecular forces of the sample.  The "turbo" tool (still not sure of the line free tool) looks like it is just reversing it's square wave magnetic field at an accelerated rate which induces a faster than normal movement into the rotor and should not negatively influence the rotor's field.

I still intend to test demagnetizing on a watch I do not care about first.

Shane

[Kalanag]

Here i used a cheap demagnetizer as a line free tool:

 

[goose]

Thankyou so much!

I will try again today and let you know how it goes. I am grateful and heartened by so many kind replies.

thank you all again!!

[goose]

update: after following a combination of the above suggestions the rotor played ball and aligned perfectly. The watch is no re-assembled and running. having said that is still stops randomly, I suspect a problem with the stem / hacking part.

Thank you to all that replied it helped me enormously!!!