Archive for October, 2009

Servicing a Doxa dive watch

October 16, 2009

I recently received this Doxa Sub 600T with the complaint that the watch would not run for very long. 

Doxa 600T_0013 copy

The owner had also complained that the bracelet end link didn’t fit tight to the case on one side, and when I removed the bracelet I found out why.  The spring bar just fell apart on my bench, so very fortunate this didn’t happen while the watch was being worn:
Doxa 600T_0015 copy

Opening the case, the ETA 2824-2 is seen:

Doxa 600T_0016 copy

Here the hands and dial have been removed:

Doxa 600T_0022 copy

Now I start removing the calendar:

Doxa 600T_0026 copy

Here the winding/setting mechanism has been removed:

Doxa 600T_0027 copy

Now to the top plate, and the ratchet wheel has been removed.  I wanted to point this out as here there is a boss that is part of the barrel bridge that the ratchet wheel rides on.  You can see the black material where the green arrows are, and this is material that has worn off the boss at the spot indicated by the red arrow.  This movement can wear a great deal here so one reason why regular service is a good idea, even if the watch appears to run well:

Doxa 600T_0029 copy

Carrying on with disassembly:
Doxa 600T_0031 copy

Here the base plate has been stripped of all parts:

Doxa 600T_0034 copy

And everything is apart now and placed by function in the storage trays: 

Doxa 600T_0037 copy

But they don’t stay there long as up next is the cleaning machine:

Doxa 600T_0039 copy

Doxa 600T_0040 copy
Here I am applying the braking grease to the mainspring barrel:
Doxa 600T_0045 copy
Here the new mainspring has been installed in the barrel:
Doxa 600T_0047 copy

And the barrel is back together as a unit and set aside ready for the movement at a later time.  The next thing I do is lubricate and install the balance jewels, and install the balance to check the hairspring.  Here you can see the spring as it goes through the regulating pins, and it’s too far to the right and touching the inner pin, where it should be centered between the pins:

Doxa 600T_0052 copy

Here the spring has been adjusted, with attention being paid to the overall centering/spacing of coils from above.  This required rotating the hairspring stud and also manually manipulating the spring:

Doxa 600T_0053 copy

Now the balance is removed and the assembly can begin, so here the barrel and barrel bridge is in place:

Doxa 600T_0054 copy

More reassembly:

Doxa 600T_0057 copy

Doxa 600T_0058 copy
Doxa 600T_0059 copy
Now we are at the point where the escapement needs to be lubricated, and the pallet stone I will oil is shown in the small blue circle:
Doxa 600T_0060 copyAfter that is complete, I place the balance cock and the balance fires right up:

Doxa 600T_0061 copy

I then check and oil the reversing wheels, and assemble the bridge

Doxa 600T_0066 copy

So now to assemble the calendar:

Doxa 600T_0069 copy

Now it’s time to put this back together, so the dial and dial spacer are first:

Doxa 600T_0088 copy

Then the hands are pressed on, paying attention to the date change so that it’s within the tolerances:

Doxa 600T_0090 copy

Now the watch is cased:

Doxa 600T_0094 copy

And I install the auto-winding bridge:

Doxa 600T_0096 copy

And onto the timing machine for initial regulation:

Doxa 600T_0097 copy

Once that’s done, time to close it up and do some extended timing and power reserve tests:

Doxa 600T_0099 copy
Doxa 600T_0103 copy
Ben Debaufre_0024 copy

The next step is checking the water resistance of this watch.  For this I use 2 machines.  The first is the Witschi Proofmaster S dry pressure testing machine.  This machine is set to the dive watch program, which first subjects the watch to a -0.7 Bar vacuum, and then a +10 Bar pressure.  The watch is constantly measured to detect deflection in the case, and through those measurements determines if the watch is water resistant.  Here the watch is ready to be mounted in the chamber:

Doxa 600T_0104 copy

And here the test is complete, and I have magnified the results screen and inset it into the photo:

Doxa 600T_0106 copy copy

But we aren’t done yet.  This watch is rated to 600 m or 60 Bar, so a test at 10 Bar won’t really tell us if it’s performing as it should.  For that we use a wet testing machine.  There is some risk with this second test, as the process basically involves trying to force water into the case at high pressure:
Doxa 600T_0108 copy

The watch is placed in the holder, and then into the test chamber.  The test chamber is filled with distilled water to the very top:

Doxa 600T_0109 copy

The lid is placed trying not to allow any bubbles inside the chamber:

Doxa 600T_0110 copy

The watch is tested at a higher level than it’s rated capacity, so for a 60 Bar watch, the machine is set to 70 Bar, or just over 1,000 pounds per square inch:
Doxa 600T_0111 copy

The watch is left at this pressure for 2 hours, then I come back and lower the pressure, and remove the watch:

Doxa 600T_0115 copy

The watch is dried off and placed on a heating station that heats the watch to 47 degrees C:

Doxa 600T_0116 copy

30 minutes later, I return and place a few drops of room temperature water on the watch crystal:

Doxa 600T_0117 copy

I wait a couple of minutes and then wipe the water off.  If the watch has leaked the inside of the crystal will have fogged, but this one is clean:

Doxa 600T_0119 copy

The bracelet was mounted and the watch returned to the client.

I hope you enjoyed seeing how a modern dive watch is serviced.  If you have any questions or would like to have your watch serviced, please contact me at

Cheers, Al