Wednesday, May 15, 2013

Quartz Time

The next big test for the first year watch students is SAWTA #2.  In this exam, we are tested on polishing and the overhaul (troubleshooting, cleaning, oiling, assembly, casing) of a quartz movement.  This week I have been practicing as much as I can on working on these quartz movements.

There are challenges unique to the electronic watch.  You must be very careful to not touch the coil as it is made of extremely fine wire and the slightest slip will kill the watch.  You must also take care when handling the integrated circuit.  The stepping motor's rotor is a strong permanent magnet which can collect metal dust which will adversely effect performance.

I have outlined some of the tests for a full service of a quartz watch below.

Checking the continuity of the coil.  1.59koh is within tolerance on this circuit
Daily rate is +0.16s/d, Consumption is 742nA

This is the consumption of the circuit without the motor active, 112nA

To test the lower voltage operating threshold and the end of life indicator, you arrange the test probes in this manner. Then slowly dial back on the voltage until the watch stops ticking

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