Omega 620 Complete Service - Omega De Ville

[Lawson]

Omega 620 Complete Service

I'm servicing a nice vintage Omega DeVille for a friend at work, and I promised her I'd post a walkthough of the service online so she could see the progress.

It's an old 2 hand mechanical, which is rare to find in the DeVille range these days, and it has nice patina on the Dial.
Along with the service to the movement, it will need a new leather strap, as the original one has succumb to age.

I'm glad that the glass is in good condition, as replicating it would be an endeavour to say the least; and fitting a standard flat glass would take away from the elegance of this timepiece.

It's only fitted with a dust-proof snap back, so I was expecting to see the normal amounts of corrosion on the stem, and keyless work.

But I was pleasantly surprised to find virtually no corrosion on the stem or movement. 
So this watch has definitely been well looked after, and from the markings inside the Caseback it has also seen it's share of trips to the watchmaker for servicing in it's lifetime.

From my initial inspection the first issue I noted was a suspected broken Mainspring, as the Crown spun freely whilst in the winding position with no resistance felt against the Click.
Now the watch is open, and can see there is damage to the Crown Wheel and Ratchet Wheel, I am even more confident my first thoughts were correct; but I'll know for sure when I open the Barrel.

There are also a couple of fibres inside the case.  You can see one here resting on the incabloc setting of the Balance.
So a good clean and service, along with a new Mainspring, should see this little 620 movement running nicely for my work colleague.

I don't have time to strip the movement and remove the Barrel until the weekend. 
But in the meantime I will get pre-approval for the purchase of a new Mainspring from the owner, so once I've removed the Barrel and confirmed it's broken I can place the order.

Is the Mainspring truly broken?
Will the owner agree to spring for a new Mainspring?
Does Mark enjoy wearing 70's disco outfits at that Retro Nights more than he lets on?

All these questions and more will be answered in the next episode!!
So stay tuned .... same Watch Time, same Watch Channel!!

Edited May 4, 2016 by Lawson

[Geo]

I'm waiting in anticipation, 'cause I do like a good walkthrough!

[bobm12]

Hi Lawson,

It is good to see you back and doing what you love doing. Your walkthrough is excellent and I'm very anxious to see the rest!

Cheers,

Bob

[Cad101]

Nice walktrough I cant wait for next weeks episode I was half expecting Benson to make an appearance

[Lawson]

Flopin Flip Flop Watchman! 
You were right!  It WAS a broken Mainspring!

Yes Pallet Boy!  And this can be the work of only one man!

You mean the "Overwinder"?

Precisely, Boy Blunder!

Approval was given by the owner, and the part has been ordered through CousinsUK ... so it should arrive in Australia in around 10 days.

Edited May 5, 2016 by Lawson

[ramrod]

this is a very nice write up.of course, the question of mark's disco outfit is worth waiting for also.

[Lawson]

Before we remove the hands and dial from the movement, I wanted to clean the dirt that had built up around the edge of the dial.

This has to be done with great caution and a gentle hand. 
Firstly get a piece of pegwood and a very sharp knife.

With the knife, feather the end of the pegwood to create a fine bristled brush, and use that along with some Rodico to remove the dirt.

 

Remember!  Always err on the side of caution ... it's better to stop early, use the Rodico to clean away the loosened dirt, and check your progress; then to continue on for too long and damage the finish on the dial.  Also, avoid the temptation to use cleaning fluids on a dial with a finish this old, as it will quickly remove the old varnish and destroy the patina.  Slow, gentle, dry cleaning is the way to go.
As you can see below I didn't remove all the dirt stains, and ceased when I was convinced continuing would only risk marking the dial.  But the end result is still a much improved dial face with the patina in tacked.

 

Disassembly

378_Omega 620 New.pdf

Firstly lift the hands, and then remove the Dial. 
The Dial is held on with two screws around the side of the Main Plate.

I was pleasantly surprised to find no corrosion whatsoever behind the Dial or on the face of the movement.
I then removed the Hour Wheel.

Once the Hour Wheel is removed, place the movement in a 4039 holder and removed the Balance.

Check there is no power held in the Mainspring, and then remove the Pallets. 
I like doing this first before removing the Canon Pinion to avoid any possibility of damaging the Pallets.

Now, turn the movement over and pull the Canon Pinion.

With the Canon Pinion now removed, turn it back over to begin striping the train.
Start by removing the Crown and Ratchet Wheels.

Remove the Barrel Bridge.

Unscrew the Click and remove the Click Spring.
Note the fibres in-between the spring.

As there is a suspected broken Mainspring in this movement I removed the Barrel it this stage, which can be done without any risk to the train.  It also helps to access the wheels to check end-shake before removing the Train Bridge.

Just as suspected the Mainspring is broken and will need to be replaced.

Next remove the Train Bridge.

Then remove the Wheels.

As seen pictured at the end of the Stem, there was a serious lack of lubrication.  Even the grease had completed dried out.

Turn the movement over and remove the Setting Lever Spring.

Followed by the Minute Wheel.

Again the evidence of died out lubrication is seen in the jewel under the Minute Wheel.

Next remove the Setting Wheel, Yoke and Yoke Spring.

 

Unscrew the Setting Lever and pull the Crown, Stem, Winding Pinion and Clutch out.

The Omega 620 Movement is now complete disassembled and ready to be cleaned.

I hope you enjoyed this walkthrough, and it can serve to help.

 

Edited May 6, 2016 by Lawson

[Lawson]

Just a quick update on the progress of the 620 service.

As I am still waiting for the Mainspring to arrive from the UK I took the time to clean the Case and Caseback.
The condition of the Case was good, with just the typical dirt and grime between the Lugs and around the Pendant.

With a little gentle cleaning the finish on the Case came up rather nicely.

So now it's just a waiting game for the part to arrive and assembly to begin

 

[Lawson]

The replacement mainspring arrived at last, so it's time to assemble the movement.

To install the new Mainspring, keep the coloured side of the keeper up and press gently into the Barrel with Brass Tweezers.  Then install the Arbor .

Then replace the Barrel Cover.

After discussing this movement with a master watchmaker and good friend, he recommended using Jizma Green to lubricate the Arbor.

Install the Barrel and Setting Lever Screw.

Then replace the Mainspring Bridge.

Install the Click Spring.

Then the Click.

Now install the Escape Wheel.

Next install the Fourth Wheel.

Then the Third Wheel.

Lastly the Center Wheel.

Carefully place the Train Bridge over the wheels, align the pivots and secure.
Be sure to always test the free running of the train before completely tightening down the bridge.

Now install the Ratchet Wheel.

And then the Crown Wheel and Crown Wheel Core.

Flip over the movement and place the Clutch Wheel and Winding Pinion.

Insert the Stem and then install the Setting Lever.

Replace the Yoke and Yoke Spring.

Press the Canon Pinion in place.

Now install the Minute Wheel and Setting Wheel.

Then replace the Setting Lever Spring and Hour Wheel and check it's function,
then remove the Hour Wheel to avoid it falling out as the movement is flipped.

Flip the movement over and install the Pallet and Pallet Cock.
Give the Crown a few winds and test the Pallet's action is free.

Then install the Balance, remove the incablocs, lubricate and re-install.

Turn the movement over again and after replacing the Hour Wheel secure the Dial.

Fit the Hands.

Place the movement in the Caseback.

Then snap the Top Case in place, and fully test the watch's functions.

Check and calibrate the movement on a Timegrapher, and the service is complete.

This has been an extremely satisfying movement to service, and I'm sure it will give
it's owner many years of pleasure to wear

I also trust it helps others and gives them the confidence to tackle the service of this movement.

[noirrac1j]

On 5/5/2016 at 10:06 AM, Lawson said:

Flopin Flip Flop Watchman! 
You were right!  It WAS a broken Mainspring!

Yes Pallet Boy!  And this can be the work of only one man!

You mean the "Overwinder"?

Precisely, Boy Blunder!

Approval was given by the owner, and the part has been ordered through CousinsUK ... so it should arrive in Australia in around 10 days.

Awesome! I love when the mainspring is broken...funny post Lawson!

 

JC