Coelho wrote:Dear Friends, Recently replaces a quartz crystal of a Frontier module, because as you know old crystals oscillate faster, therefore Advances! However after replacing the quartz crystal my Frontier continues to advance more than expected to a quartz clock. Can anyone help me to know why?
Hug.
The reason your watch is advancing in time, assuming the new quartz crystal is good, is because the quartz crystal is not being loaded with the correct value of load capacitance. Frontier LED modules all have two capacitors in the oscillator circuit. One is a fixed surface mount capacitor with a value of around 24 pico farads, the other a "trimmer" capacitor which can be adjusted from about 5-35 pico farads. Stray capacitance of the input and output of the oscillator amplifier, plus other parasitic substrate capacitance adds to the value of these two capacitors. The "trimmer" adjust can be seen through a hole in the plastic carrier on the backside of the module and the hole in the battery clip on some modules. Without instrumentation to indicate the frequency at which the quartz is actually oscillating makes it a bit difficult to get the oscillator set to 32.768KHz, the ideal frequency for no gain or loss of time. One way of trying to reduce the error is to adjust the trimmer capacitor in the module with a small bladed screwdriver, ideally made from a non metallic material. Which direction to turn the adjustment depends upon which way the trimmer capacitor was installed on the substrate during the manufacturing process. Try the following "hit and miss" method to reduce the error. This process will take a week or so to complete, so be patient.
1.Access a known time standard on the internet such as the U.S. official time @;
http://time.gov/HTML5/
2. Enter the "set" mode of the module and set "minutes" to one minute ahead of the"time standard". (The hours, month, date, day of the week do not have to be set correctly.) Sync the modules "minutes" with the "time standard", that is, in the "set" mode with a "blinking" cursor showing in the display of the module, push the "command" button of the watch when the "time standards" seconds roll over to "00". This will sync the modules "seconds" with that of the standard. For instance; if the "time standard" shows 12:05:19 pm, set the modules minutes to indicate XX:06. At this point continue to push the "set" command button until you obtain a "blinking" cursor. As the "time standard" rolls over from 12:05:59 to 12:06:00 engage the "command" button to sync the module to the "time standard". Once this is done, pushing the modules "command" button and holding it down will show the seconds of the module ticking off. They should be in sync with the "time standards" seconds.
3. Remove the watch case back. Since you already know that the time is running fast, adjust the "trimmer capacitors" adjustment in either direction about 1/4 turn. Note which direction, from the original setting you turned the adjustment. At this point you wait for 24-48hrs. or so to see if the module is still running fast. In order to check, you must have the modules battery clip in electrical contact with the watch case, otherwise the display will show nothing when the "command" button is pressed. Rather than removing and replacing the watch case back every 24-48hrs., use a piece of aluminum foil to make contact between the battery clip and the watch case as you press the "command" button. Hold the "command" button down so that you can see the "seconds" ticking off and compare them with the "time standard". Make a note as to the difference of seconds between the "time standard" and the module. Still running fast? Re-sync the module with the "time standard" as outlined in step 2 above. Turn the "trimmer" adjustment another 1/4 turn in the same direction as noted earlier. Wait another 24-48hrs and re-check the sync between the "time standard" and the module. Again note the time difference in seconds between the "time standard" and the module. Repeat if the module is still running fast. If the module has "lost" time, re-sync with the "time standard" and re-adjust the "trimmer" a very small amount in the OPPOSITE direction from the starting direction. You can continue the above procedure until your satisfied with the modules time keeping ability.
4. If you never find a point in the adjustment range of the "trimmer" that the modules time will not go from being fast to slow, either the new quartz crystal is being driven to hard and forced to oscillate at a higher frequency or mode, is too far off frequency to be pulled on to 32.768KHz with the load capacitances presented, the "fixed" surface mounted capacitors value is to low, or the "trimmer" itself is faulty.
Some jewelers have instrumentation to indicate how fast or slow the quartz oscillator is running without removing the module from the case. They can also pop the back from the case to adjust the oscillator in real time. You might check with jewelers in your area. If worse comes to worse, send me your module and I can tweak it to correct its time keeping ability, no charge, you pay postage both directions.
Hope this long winded post helps.
Joe