My Casio Scientific 197 alarm no longer functions. I have tested the signal from the watch module between the tiny coiled spring and the thin flat springy metal that each contact one of both surfaces of the thin flat rectangular piezo buzzer mounted on the interior rear cover of the watch. The coiled spring contacts the piezo surface directly and the springy metal contacts the rear watch cover on which the piezo is mounted. A scope shows a signal present that appears to be similar to the alarm sound when it functioned.
I made contact between an inset reset point within the watch module and the positive side of the watch battery to activate the LCD display. There is a second inset point next to the thin coiled alarm spring. I do not know if this is a reset point for the alarm to be used as with the display - perhaps controlling the volume of the detected scope signal to the piezo. Any information on the function of this inset point would be appreciated.
Both the springy metal and coiled spring are sufficiently extended to make good contact when the rear watch cover is replaced. I note that the surface of the piezo where the spring contacts is worn such that an ohm meter shows a high resistance between that point and the other surfaces. Contacts between other surfaces on the same side of the piezo show readings close to a short circuit. I suspect that the point of contact for the spring must be for the whole piezo surface so that this point should read a short circuit as well. I presume the piezo material must be surfaced on both sides with a conductive material for it to function.
What can I do to resurface the piezo spring contact point to make it electrically conductive with the remainder of the surface and not damage the piezo material, or is the piezo beyond repair and can it be replaced?
I made contact between an inset reset point within the watch module and the positive side of the watch battery to activate the LCD display. There is a second inset point next to the thin coiled alarm spring. I do not know if this is a reset point for the alarm to be used as with the display - perhaps controlling the volume of the detected scope signal to the piezo. Any information on the function of this inset point would be appreciated.
Both the springy metal and coiled spring are sufficiently extended to make good contact when the rear watch cover is replaced. I note that the surface of the piezo where the spring contacts is worn such that an ohm meter shows a high resistance between that point and the other surfaces. Contacts between other surfaces on the same side of the piezo show readings close to a short circuit. I suspect that the point of contact for the spring must be for the whole piezo surface so that this point should read a short circuit as well. I presume the piezo material must be surfaced on both sides with a conductive material for it to function.
What can I do to resurface the piezo spring contact point to make it electrically conductive with the remainder of the surface and not damage the piezo material, or is the piezo beyond repair and can it be replaced?
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