Eta 955 Service Walkthrough "the Workhorse Of Highend Quartz"

[Lawson]

ETA 955 Service Walkthrough "The Workhorse of Highend Quartz"

 

The ETA 955 and 956 Quartz Movements are the most commonly found movement in high-end quartz watches with three hands and a date feature.  You will find them in Omega, Tag, and many other brands on the market.

 

For this walkthrough I will be using an 955.412 Movement as my example; but the 956 is so similar to the 955, that this walkthrough will suffice for both. 

Please note that the numbers after the decimal place only relates to the factory in which the movement was made, so yours could read 955.112, or another factory number ... regardless, the parts are identical and interchangeable.

 

 

As with all movements, quartz or mechanical, they have a service interval that should be adhered to for longevity of the movement.  With quartz movements when the lubrication becomes dried out, or the movement becomes dirty, they will draw more and more current from the battery in order to maintain accurate time keeping.  The ETA 955/6, when in optimum condition should draw around 800nA ~ 1.5uA, if the movement is drawing more power than this, a service is required.  If a service is not performed, the battery life with decrease markedly, and can go as far as drawing more power from the battery than it was designed for, and damage the battery and cause it to leak and corrode your valuable time piece.

 

Service Manual for the 955/6 Movement

CT_956412_FDE_493024_06.pdf.PDF

 

Disassembly

 

Remove the two Date Wheel Keepers.

I always start with the one holding the Date Jumper Spring in place.

 

 

Sometimes the Date Jumper Spring can ping out of place, so be careful when removing the keeper plate above it.

Here is a reference photo in case it moves before you see how it's properly seated.

 

 

Next remove the Keepers and Date Wheel.

Then remove the Date Jumper Spring, Motion and Calendar Work.

 

 

This will leave only the Keyless Work; remove the Yoke and the Sliding Pinion only.  We need to flip the movement over, and disassemble the IC Board before we can remove the rest of the Keyless Work.

 

 

With the movement flipped over, remove the 3 screws holding the Coil Protector.

Note for re-assembly the Gold Screw in the centre.

 

 

Now that the Coil Protector is removed, GREAT care must be taken not to damage the exposed fine windings of the Coil.

 

 

Then to remove the IC Board, simply remove the 2 remaining screws that hold it.

Do this slowly and carefully, as you do not want to slip off the screw and damage this delicate circuit.

The same level of care needs to be taken when removing the IC Board from the Main Plate. 

Take your time and carefully lift it off and store it immediately out of harms way.

 

 

Next remove the black Insulator Block, and Battery Insulator.

This will expose the Setting Lever Spring Clip, which will enable you to remove the rest of the Keyless Work.

 

 

To remove the Setting Lever Spring Clip, place both points of your tweezers on the locations where I've placed the stars and gently push down on the spring. Then with a piece of Pegwood, push the spring in the direction of the arrow until it moves to the larger opening slot.

 

 

This will now allow the Setting Lever to be removed, along with the rest of the Keyless Work.

 

 

Next remove the Stop Lever and Switch, and remove the one screw holding the Train Bridge in place.

 

 

Then carefully remove the Gear Train and the Rotor.

 

 

The movement is now completely stripped and ready for inspection and cleaning.

 

 

There are some parts that you do not place in the parts cleaner, they are as follows:

Date Ring

Rotor

IC Board

The rest should be demagnetized prior to cleaning to avoid any metal particles in your cleaning solution from sticking to your parts.  When cleaning I also including the Insulator Block, and Battery Insulator in the basket, normal watch cleaning solutions do not harm these items and it is essential they are completely clean to provide the best insulation possible.

 

 

The Rotor should be cleaned by use of Rodico.  As you can see from the picture below, it's surprising the dirt and old oil this will remove ... and it is sufficient cleaning for the Rotor.

 

 

I hope this has been a help to you, and I will post the assembly procedure later today, if time permits.

[clockboy]

Excellent post Lawson. Will be interested in the assembly & the lubrication used.

[Geo]

Really well done and illustrated as usual Lawson, keep them coming! :)

[WillFly]

Excellent - detailed and instructive!

[frenchie]

Excellent, thank you !!

[bobm12]

A masterful tutorial my friend. Complete and very detailed. I like the tips included! You are the man! :bow:

 

By the way, do you have a way to troubleshoot these electronic movements, like checking when the coils, circuits, etc are faulty? I happen to have a couple of similar non working movements and some extra coils and whatnots. Would be great if I could figure out what to check and measure so I can fix them. Regretfully, after many years of non using any electronics troubleshooting and instrumentation I've lost that skill on the most part...so I may need a refresher! :(

 

In any case, as Geo said, keep them coming!

 

Cheers,

 

Bob

[Lawson]

bobm12, on 25 Jan 2015 - 04:03 AM, said:

 

By the way, do you have a way to troubleshoot these electronic movements, like checking when the coils, circuits, etc are faulty?

 

Cheers,

 

Bob

 

Thanks for the kind replies my friends.

Bob, yes I have a way to troubleshoot the electronics of the quartz movement; but not at home :(

Even cheap ones are around AU$1000.00, and I'd be dubious of there reliability.

 

At present, this is the unit I am using made by Witschi, and it has trouble sensing some of the new Chinese movements with the probes; and you have to place a battery in them put them on the mic block to the far left.  But even this old model run at around AU$2700.00

 

 

The really good one is this model.  The Witschi Analyzer Q1

But at over AU$6000.00 for one ... FOR GET IT!

 

 

If anyone has FIRST HAND experience with a cheaper alternative, that works well and reads reliably both Swiss and Asian movements, I'd be appreciate them chiming in, as I would like to get one for home.

[bobm12]

I've read about those and they are a dream that might never happen. I was just thinking about regular multi-meter (stone age maybe?) type of troubleshooting. So far I test only continuity on coils but I'm afraid to use other functions on the meter for different parts. I think I could burn something with the current generated by the tool. For example, impedance and how to measure it safely on coils...and then the actual circuit. Lots and lots of questions yet! Nice to have a tutorial of someone doing it.

 

By the way, you said you demagnetized certain parts. How did you do that? Did you hold them down on something and then did the trick with the demagnetizer? Everytime there are lots of smaller parts on the loose they bounce around in my demagnetizer so the purpose of it is lost...

 

In any case, many questions and all thanks to your great tutorial...without it, they wouldn't have surfaced! Way to go Lawson and long way for me to learn this side of the trade!

 

Cheers,

 

Bob

Edited January 25, 2015 by bobm12

[Lawson]

bobm12, on 25 Jan 2015 - 11:13 AM, said:bobm12, on 25 Jan 2015 - 11:13 AM, said:

I was just thinking about regular multi-meter (stone age maybe?) type of troubleshooting.

 

The four items that need to be tested are Current Draw, Coil Continuity, IC Function, and Quartz Oscillation.  I not sure, but I think the only thing that can be tested with a Multi-Meter is the Coil  :(

 

 

bobm12, on 25 Jan 2015 - 11:13 AM, said:bobm12, on 25 Jan 2015 - 11:13 AM, said:

By the way, you said you demagnetized certain parts. How did you do that? Did you hold them down on something and then did the trick with the demagnetizer? Everytime there are lots of smaller parts on the loose they bounce around in my demagnetizer so the purpose of it is lost...

 

Cheers,

 

Bob

 

I demagnetize the parts in my small parts container ... you know, the one you put all the wheels and spring and screws into.  Seems to work really well.

Edited January 25, 2015 by Lawson

[bobm12]

Excellent, I'll try that next time. Thank you Lawson!

[Lawson]

Assembly

 

I have made the assembly walkthrough much more detailed, as putting things back together is always more tricky than pulling them apart :)

 

 

Firstly install the Setting Lever Jumper and the Double Corrector Operating Lever.

D5 on the Corrector Lever Pivot

9501 on the Setting Jumper

 

 

To install the Setting Lever, first move the Double Corrector Operating Lever to it's most outward position, then push the Setting Lever 1/3 of the way down it's pivot, next place a 1.00mm screwdriver as shown below, and turn it clockwise.  This will push the Setting Lever Jumper over to the other side of the pin on the underneath of the Setting Lever.  Then push the Setting Lever home, making sure that the pin on the Double Corrector Operating Lever locates inside it's guide slot on the Setting Lever.  I know this sounds a little complicated; but once you study the Keyless Work, you will understand the procedure I've explained here.  Just take your time, and read through this procedure whilst looking at your work a couple of times until you are sure you've got it.

Please Note: If you use a larger size of screwdriver be careful you don't push it too far over and bend the jumper ... using a 1.00mm driver is the correct size and will avoid this possibility.

9501 on the Setting Lever pivot

9501 in the guide for the Corrector Lever pin

 

 

Flip the movement over and place the Setting Lever Spring Clip as shown below

 

 

Then with a pair of tweezers push down on both sides of the clip and with a piece of Pegwood push it inwards so it locks in.

 

 

Next install the Rotor, and you'll find due to it being magnetized, it will stick to the Stator.  DO NOT try and locate it in it's jewel, as it will just pop out and stick to the Stator again, and this can be very frustrating ... but I have a little trick that will cure this :)

 

 

Place one of the screws on the opposite side of the Main Plate, behind where the Rotor is located, and you'll see it will be attracted to the Rotor (as seen below).  This little screw will pull the Rotor downwards and stop it being pulled over by the Stator, so you now can locate it in it's jewel.

Don't forget to remove and demagnetize the screw once you've completed installing the gear train.

 

 

There is a LOT of discussion on oiling quartz gear trains.  The ETA Service Manual says to use Moebius 9014 on this particular movement; but I prefer Moebius Quartz Oil, as it can be used on both metal and plastic gears without concern ... why have 2 oils when 1 will suffice for both applications.

Others say, don't oil the gear train at all, as it just adds load to the movement and makes it draw more current.  Personally, I'd rather change a battery a little earlier than change out a worn out movement ... you choose which is cheaper.

 

 

When oiling any quartz gear train, we only apply about half of what you'd use on a mechanical movement ... it's called Ghost Oiling.  That being said, ghost oil the jewel for the Third Wheel with Quartz Oil as shown below.

 

 

Ghost Oil the upper part of the Second Wheel with Quartz Oil as shown below

 

 

Fit the Gear Train into the Main Plate.

 

 

Place the Gear Train Bridge over the wheels, locate the pivots carefully until all are freely spinning, and tighten down the bridge.

Remember once the screw makes contact with the bridge, STOP, and recheck the free spinning of the train before completely tightening the screw.

Once the Bridge is secure, place the Stop Lever and Switch back onto it's pivot.

D5 for Stop Lever and Switch pivot

Quartz Oil for all Gear Train pivots (remember to oil both sides)

 

 

Next install the Battery Isolator, making sure to push the tab into it's slot as shown below.

 

 

Then install the Isolator Block

 

 

Next we need to short out the screws for the IC Board.

You'll see there is a Gold Screw, this is for the Coil Protector, and then there are three screws of the same length, and one shorter one.  The shorter screw must be place into it's correct hole.

 

 

Locate the IC Board onto the movement.

Before I screw the IC Board down, I always fit the Coil Protector first.  This helps avoid any damage if you accidently slip off a screw head.

Remember to use the Gold Screw.

 

 

Next place all the rest of the screws into their holes, noting the position where the short screw is to be located.

 

 

This side of the movement is now complete.  Time to flip it over and complete the Keyless Work, Motion Work and Calendar Work.

 

 

Place the Sliding Pinion into it's position. 

Please Note this is a spare movement I'm using here, and I don't have a stem.  If you have a stem, now is the time to install it.

9501 in the grove for the yoke on the Sliding Pinion

9501 on the stem

 

 

Place the Yoke into position

D5 on Yoke Pivot

 

 

Install the Setting Wheel and Date Corrector

D5 on Setting Wheel pivot

D5 on Date Corrector slot

 

 

Next is lubricating the Cannon Pinion.  This is one step that MUST be done correctly, otherwise too much friction will occur and you'll damage the Setting Wheel in short order.

9501 Canon Pinion fiction points

 

 

Place the Canon Pinion and then the Minute Wheel

D5 Minute Wheel pivot

D5 Ghost Oil the Canon Pinion Tube

 

 

Attach the Motion Work Bridge and secure it down.

 

 

Place the Date Ring onto the movement, and then slide the Date Indicator Driving Wheel into place, so the teeth of the Date Wheel are inside the Driving Wheel.

Then install the Intermediate Date Wheel.

D5 Date Indicator Driving Wheel pivot

D5 Intermediate Date Wheel pivot

 

 

Lubricate the foot of the Date Jumper Spring as shown below

9501 Date Jumper Spring foot

 

 

Place the Date Jumper Spring into position on the movement

 

 

Place the Date Jumper Maintaining Plate and secure it.

 

 

Check the date and time setting, making sure the quick date works smoothly.  Check the feel of the Motion Work, making sure there is not too much or too little friction from the Canon Pinion.

 

Your movement is now completely serviced, all that's left to do is fit Hour Wheel, Dial and Hands  :woohoo-jumping-smiley-emoticon:  

It's good for another 100,000 miles or 5 years ... whichever comes first ^_^

I hope this walkthrough both helps and encourages you with servicing your 955/6 ETA Movement

[clockboy]

Absolutely brilliant walk through.  5 *****

I have always wondered what lubrication should be used on a quartz & now I know. The location of the rotor trick with the screw is also a great idea.

[bobm12]

I think clockboy has said it all! Great tutorial Lawson!

 

Chears,

 

Bob

[Geo]

Brilliant presentation Lawson, you have set the standard!

I can see you producing "Haynes Manuals" for watches shortly! :)

[Lawson]

Don't forget that Mark has made a video on this movement as well. 

Much better produced than anything I can do :)

 

 

[Geo]

My comment is regarding still photography and text, not video. :)

[noirrac1j]

WOW That's all I can say! I have no intention of ever servicing a quartz movement, but I read so carefully every single part that when you wrote.." this is one step that MUST be done correctly," I think I even held my breath!  Very good pictorial walk-through.

 

JC

Edited February 1, 2015 by noirrac1j

[clockwatcher]

I recently acquired a non-running Favre-Leuba quartz with a 955 movement - cheaply of course! Between Lawson's and Mark's coverage of the servicing I hope that, when I become more proficient and confident, they'll see me through the process on mine. All I can say for the time being is that a new battery didn't fix it.

More like this please.

[Profundus]

Simply fantastic walk-through, thank you! 

[Neileg]

I know this thread has been dormant but it just saved me from high blood pressure after I dislodged the keyless works on a 956 during a date wheel swap.

Many, many thanks

Neil

[RRRobert]

Somehow, the date is not aligning properly with the window.  What have I missed, or is there an alignment function ?

Thank you so much for your insight.

[jdm]

4 hours ago, RRRobert said:

Somehow, the date is not aligning properly with the window.  What have I missed, or is there an alignment function ?

Check wear and shape of of the date wheel and date jumper. 

BTW on our friendly forum it's appreciated that new members introduce themselves even before asking questions. 

[canthus]

On 1/24/2015 at 4:50 AM, Lawson said:

ETA 955 Service Walkthrough "The Workhorse of Highend Quartz"

 

The ETA 955 and 956 Quartz Movements are the most commonly found movement in high-end quartz watches with three hands and a date feature.  You will find them in Omega, Tag, and many other brands on the market.

 

For this walkthrough I will be using an 955.412 Movement as my example; but the 956 is so similar to the 955, that this walkthrough will suffice for both. 

Please note that the numbers after the decimal place only relates to the factory in which the movement was made, so yours could read 955.112, or another factory number ... regardless, the parts are identical and interchangeable.

 

 

As with all movements, quartz or mechanical, they have a service interval that should be adhered to for longevity of the movement.  With quartz movements when the lubrication becomes dried out, or the movement becomes dirty, they will draw more and more current from the battery in order to maintain accurate time keeping.  The ETA 955/6, when in optimum condition should draw around 800nA ~ 1.5uA, if the movement is drawing more power than this, a service is required.  If a service is not performed, the battery life with decrease markedly, and can go as far as drawing more power from the battery than it was designed for, and damage the battery and cause it to leak and corrode your valuable time piece.

 

Service Manual for the 955/6 Movement

CT_956412_FDE_493024_06.pdf.PDF 1.81 MB · 319 downloads

 

Disassembly

 

Remove the two Date Wheel Keepers.

I always start with the one holding the Date Jumper Spring in place.

 

 

Sometimes the Date Jumper Spring can ping out of place, so be careful when removing the keeper plate above it.

Here is a reference photo in case it moves before you see how it's properly seated.

 

 

Next remove the Keepers and Date Wheel.

Then remove the Date Jumper Spring, Motion and Calendar Work.

 

 

This will leave only the Keyless Work; remove the Yoke and the Sliding Pinion only.  We need to flip the movement over, and disassemble the IC Board before we can remove the rest of the Keyless Work.

 

 

With the movement flipped over, remove the 3 screws holding the Coil Protector.

Note for re-assembly the Gold Screw in the centre.

 

 

Now that the Coil Protector is removed, GREAT care must be taken not to damage the exposed fine windings of the Coil.

 

 

Then to remove the IC Board, simply remove the 2 remaining screws that hold it.

Do this slowly and carefully, as you do not want to slip off the screw and damage this delicate circuit.

The same level of care needs to be taken when removing the IC Board from the Main Plate. 

Take your time and carefully lift it off and store it immediately out of harms way.

 

 

Next remove the black Insulator Block, and Battery Insulator.

This will expose the Setting Lever Spring Clip, which will enable you to remove the rest of the Keyless Work.

 

 

To remove the Setting Lever Spring Clip, place both points of your tweezers on the locations where I've placed the stars and gently push down on the spring. Then with a piece of Pegwood, push the spring in the direction of the arrow until it moves to the larger opening slot.

 

 

This will now allow the Setting Lever to be removed, along with the rest of the Keyless Work.

 

 

Next remove the Stop Lever and Switch, and remove the one screw holding the Train Bridge in place.

 

 

Then carefully remove the Gear Train and the Rotor.

 

 

The movement is now completely stripped and ready for inspection and cleaning.

 

 

There are some parts that you do not place in the parts cleaner, they are as follows:

Date Ring

Rotor

IC Board

The rest should be demagnetized prior to cleaning to avoid any metal particles in your cleaning solution from sticking to your parts.  When cleaning I also including the Insulator Block, and Battery Insulator in the basket, normal watch cleaning solutions do not harm these items and it is essential they are completely clean to provide the best insulation possible.

 

 

The Rotor should be cleaned by use of Rodico.  As you can see from the picture below, it's surprising the dirt and old oil this will remove ... and it is sufficient cleaning for the Rotor.

 

 

I hope this has been a help to you, and I will post the assembly procedure later today, if time permits.

Great report, have done many quartz (cheap and better), but never thought of the screw trick.  Will certainly use in future.  I have a very small sterile pot which I keep the rotor in separately if assembly is delayed, this is to keep it clean after removing debris etc with rodico.

Edited August 15, 2019 by canthus
Add text

[RickTock]

@Lawson, thank you so much for posting this! I just finished up servicing of a 555.415 movement, and your detailed write-up was a great help. Screw behind the rotor trick was worth GOLD! I spent hours fiddling prior to reading that... Much appreciation!

[Colditz]

On 1/25/2015 at 1:13 AM, bobm12 said:

I've read about those and they are a dream that might never happen. I was just thinking about regular multi-meter (stone age maybe?) type of troubleshooting. So far I test only continuity on coils but I'm afraid to use other functions on the meter for different parts. I think I could burn something with the current generated by the tool. For example, impedance and how to measure it safely on coils...and then the actual circuit. Lots and lots of questions yet! Nice to have a tutorial of someone doing it.

 

By the way, you said you demagnetized certain parts. How did you do that? Did you hold them down on something and then did the trick with the demagnetizer? Everytime there are lots of smaller parts on the loose they bounce around in my demagnetizer so the purpose of it is lost...

 

In any case, many questions and all thanks to your great tutorial...without it, they wouldn't have surfaced! Way to go Lawson and long way for me to learn this side of the trade!

 

Cheers,

 

Bob

When I de-magnetise small parts I put them in a plastic bag. This stops them leaping into oblivion.