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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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atomic wris****ch battery Q
hello...
I have an atomic wris****ch that after a year or so acted like the battery was worn. Specifically, the EL backlight (when depressed) would cause the numerics to momentarily blank, and the clock to default to noon. After replacing the battery, it seemed fine for a few days, and the symptoms returned. Not suspecting anything, I bought a replacement watch by another company (it had a different marking) but worked identically. Again the year went by and the story was the same. I bought the CR1620 at Walmart, and even replaced that one within a week, and had this identical problem. So this brings me now here. I measured the current in 3 states: quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA When I used a AA 3 volt pack, the issue disappeared. Eveything was fine. I suspect the current draw essentially drops the voltage below a theshold, reseting the watch. But is this normal? Can a lithium button cell be expected to sustain a 5mA draw momentarily and not reset a watch? Or am I constantly finding poor quality lithium cells? Suggestions? Perhaps a source for "good" button cells? Les KA9GLW |
#2
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atomic wris****ch battery Q
Sounds like you have bad batteries. If another 3v source (such as the
AA pack) works, i think the batteries are going bad very fast and you need to find that source of good lithiums. Hvae seen similar problems in keyless entry remotes for cars - work for a year or two, die, change batteries, work for a week or two and then die again. You just need to find high quality batteries. |
#3
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atomic wris****ch battery Q
It sounds like you have a bad source for the batteries. The readings you are
getting seem to be normal for most digital watches of this type. The backlight for the display can easily require a number of milliamps to operate. -- JANA _____ "les" wrote in message ... hello... I have an atomic wris****ch that after a year or so acted like the battery was worn. Specifically, the EL backlight (when depressed) would cause the numerics to momentarily blank, and the clock to default to noon. After replacing the battery, it seemed fine for a few days, and the symptoms returned. Not suspecting anything, I bought a replacement watch by another company (it had a different marking) but worked identically. Again the year went by and the story was the same. I bought the CR1620 at Walmart, and even replaced that one within a week, and had this identical problem. So this brings me now here. I measured the current in 3 states: quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA When I used a AA 3 volt pack, the issue disappeared. Eveything was fine. I suspect the current draw essentially drops the voltage below a theshold, reseting the watch. But is this normal? Can a lithium button cell be expected to sustain a 5mA draw momentarily and not reset a watch? Or am I constantly finding poor quality lithium cells? Suggestions? Perhaps a source for "good" button cells? Les KA9GLW |
#4
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atomic wris****ch battery Q
You might try gently cleaning the battery contacts with a pencil eraser.
"les" writes: hello... I have an atomic wris****ch that after a year or so acted like the battery was worn. Specifically, the EL backlight (when depressed) would cause the numerics to momentarily blank, and the clock to default to noon. After replacing the battery, it seemed fine for a few days, and the symptoms returned. Not suspecting anything, I bought a replacement watch by another company (it had a different marking) but worked identically. Again the year went by and the story was the same. I bought the CR1620 at Walmart, and even replaced that one within a week, and had this identical problem. So this brings me now here. I measured the current in 3 states: quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA When I used a AA 3 volt pack, the issue disappeared. Eveything was fine. I suspect the current draw essentially drops the voltage below a theshold, reseting the watch. But is this normal? Can a lithium button cell be expected to sustain a 5mA draw momentarily and not reset a watch? Or am I constantly finding poor quality lithium cells? Suggestions? Perhaps a source for "good" button cells? Les KA9GLW |
#5
Posted to sci.electronics.repair
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atomic wris****ch battery Q
James D. Veale wrote:
You might try gently cleaning the battery contacts with a pencil eraser. "les" writes: hello... I have an atomic wris****ch that after a year or so acted like the battery was worn. Specifically, the EL backlight (when depressed) would cause the numerics to momentarily blank, and the clock to default to noon. After replacing the battery, it seemed fine for a few days, and the symptoms returned. Not suspecting anything, I bought a replacement watch by another company (it had a different marking) but worked identically. Again the year went by and the story was the same. I bought the CR1620 at Walmart, and even replaced that one within a week, and had this identical problem. So this brings me now here. I measured the current in 3 states: quiescent: 3 uA, actively radio syncing: 180 uA, EL backlight : 5mA When I used a AA 3 volt pack, the issue disappeared. Eveything was fine. I suspect the current draw essentially drops the voltage below a theshold, reseting the watch. But is this normal? Can a lithium button cell be expected to sustain a 5mA draw momentarily and not reset a watch? Or am I constantly finding poor quality lithium cells? Suggestions? Perhaps a source for "good" button cells? Les KA9GLW Have you looked at your watch with a magnifiing glass or a microscope? My watch had some very nice wiskers grown on the component board. So the next battery was emptied in a real hurry!! Its in a landfill now. |
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