Maurice Lacroux Quartz Service

[Lawson]

Hi Guys,

 

It's certainly been a while since my last walkthrough, and I hope to get back to posting them on a more regular basis.

I also apologies in advance for the quality of the images, but the fluro lighting at my workstation causes havoc with the camera on my mobile phone, and I can't waste time at work setting up a good photographic light source like I can at home ... I hope you understand.

 

This one is on a Maurice Lacroux with an ultra thin Girard Perregaux quartz movement inside.

 

 

 

The customer had reported that the watch was losing time.  So I ran it up on the tester; but electrically it looked fine, with a low power consumption and accurate rate.  So I cased it back up again, set it to the correct time, and let it run for a 24hrs.  Low and behold, the next day it was 3hrs behind current time, so I suggested to the client that the fault was mechanical, and would need to be stripped down and investigated.  They agreed.

 

Once the Hands and Dial where removed, we can see this is a very small and basic two handed movement.  So the only part of the Train that traverses the Main Plate is the Third Wheel.

Also worth noting on this particular movement, the Keyless Work is riveted, and is not able to be dismantled.

 

 

So to begin disassembly, remove the Hour Wheel, then the single screw holding the Minute Wheel Cover Plate.  You can now remove the Minute Wheel and Canon Pinion.  This completes the dismantling on the dial side.

 

 

Flip the movement over and remove the Battery Keeper, Battery (Number 321) and Coil Protector.  I recommend replacing the Keeper Screws in the Main Plate, as although they are the same size and pitch; the heads are different thickness.  Also note that the screws for the Coil Protector are the two long thin screws.

 

 

Remove the last remaining screw that holds the Circuit, and remove the Circuit ... storing it in a VERY safe place.

Remove the Battery Isolator Pad at this time too.

 

 

Remove the screw that holds the Train Bridge, it's exactly the same size as the previous screw for the Circuit.

Remove the Bridge and take note of the Train layout.

 

 

Lastly, remove the Intermediate Wheel, Third Wheel and Rotor.  Be sure not to put the Rotor in with the other parts for cleaning as it is magnetic and will attract any metal particulars suspended in the cleaning solution.

 

Once clean, assembly is simply the reverse order.

 

 

Once the Circuit is back in place check that it is still functioning correctly, displaying oscillation of the Quartz Crystal, and that the "Motor" LED flashes: displaying that the Coil is impulsing the Rotor.

 

 

The Canon Pinion, then Minute Wheel are replaced, and the Minute Wheel Cover Plate re-fastened.

 

 

Then back on with the Hour Wheel, and the service is complete ... replace the Dial and Hands.

 

 

Fortunately, the only issue with this movement was contamination from age that was occasionally stopping the movement.  Once serviced it ran perfectly ... and the client was delighted.  :)

 

As always, I hope this was helpful and enjoyable to read.

[clockboy]

That is I think the same as a Maurice Lacroux I recently changed a battery for. If my memory serves me well (not often now days) . The movement was a Ronda and very nice too. I did find a tech sheet somewhere. If needed I will dig through my files & find it.

[Geo]

Another good result Lawson, plus excellent info for the masses. :)

[bobm12]

Great walkthrough Lawson. I've been having internet issues lately but had a chance to see this one but couldn't come back on time to comment. As always, a well chosen walkthrough and masterfully done.

 

Cheers,

 

Bob

[Mark]

Nice job Lawson. We built somthing similar to the witschi machine for offering a supply voltage, reading consumption and checking the coil, on the BHI course years ago, I don't know what happened to it but I really do want to make another.

 

These days we have Arduino and I feel another project tingling in my fingers! :D