27 Apr 2011, 21:10
Recently won a Pulsar P4 GF Executive on Ebay that could set time via magnet but display buttons were non-functional. Below describes the steps I did to revive this watch.
First step, I removed the module from the case and powered up the module to see if a stronger magnet would fix the magnetic reed switches for date and time. No luck.
Next step, I checked continuity of the light sensor (located above the LED display on the top right side) to the watch circuit board traces with an ohm meter, all good, if it was not I was planned to bypass the sensor and recheck the watch functions. I also checked functionality of the light sensor by varying light levels and observing the resistance change, all good.
Apparently it seems by applying pressure to the light sensor with my ohm meter probes I managed to partially revive the watch date function. The time function magnetic reed sensor still was not functioning.
Next step, I powered the module outside the case and shorted the Time function reed and the time/seconds lit up! So I confirmed the problem to be a reed sensor. Instead of replacing it I used a stronger magnet I found using an old Sonicare toothbrush magnet located at the base of the toothbrush head. I quickly and repeatedly swiped the magnet back and forth next to the reed switch to exercise the internal switch, hoping I could clean the contacts.
After about 5 minutes of exercising the switch I re-powered the module and the reed switch worked! It worked with the stronger magnet but not the watch magnet time function button. I repositioned the reed switch closer to the Time button and it worked fine. I now have a fully functional P4 Executive at a fraction of the going ebay price.
First step, I removed the module from the case and powered up the module to see if a stronger magnet would fix the magnetic reed switches for date and time. No luck.
Next step, I checked continuity of the light sensor (located above the LED display on the top right side) to the watch circuit board traces with an ohm meter, all good, if it was not I was planned to bypass the sensor and recheck the watch functions. I also checked functionality of the light sensor by varying light levels and observing the resistance change, all good.
Apparently it seems by applying pressure to the light sensor with my ohm meter probes I managed to partially revive the watch date function. The time function magnetic reed sensor still was not functioning.
Next step, I powered the module outside the case and shorted the Time function reed and the time/seconds lit up! So I confirmed the problem to be a reed sensor. Instead of replacing it I used a stronger magnet I found using an old Sonicare toothbrush magnet located at the base of the toothbrush head. I quickly and repeatedly swiped the magnet back and forth next to the reed switch to exercise the internal switch, hoping I could clean the contacts.
After about 5 minutes of exercising the switch I re-powered the module and the reed switch worked! It worked with the stronger magnet but not the watch magnet time function button. I repositioned the reed switch closer to the Time button and it worked fine. I now have a fully functional P4 Executive at a fraction of the going ebay price.
as english is not my native language..some nice pictures how and where to check would be a lot easier.