Can a photo cell sensor be replaced?

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Old 11-01-07, 05:56 PM
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Can a photo cell sensor be replaced?

I have a solar walkway lantern. It's a few years old but cost around $175. The lantern isn't working because the sensor is shot. I bypassed the sensor and the light works fine. The sensor is about the size of a pencil eraser and has 2 wires that come out of it and go into a circuit board, hopefully the problem is with the sensor and not on the board.

I was hoping I could replace the sensor and just splice the wires into the existing wires that are soldered onto the board.

Does anyone know if these can be purchased at a Home Depot/Lowes?

Also any other suggestions? Was thinking about leaving it just wired for off/on but that would be a real pain to have to turn it on and shut it off every day/night.
 
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Old 11-01-07, 06:02 PM
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That's why it has a photocell, so you won't have to turn it on and off daily. You can possibly replace the photocell, but you would need to replace it with the exact size, so a big box store may not be your best bet. Try an electronics or electrical supply house.
 
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Old 11-20-07, 02:57 PM
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I have replaced those in the past, I have some low voltage driveway lights controlled by a central photocell that I fixed. It takes a little bit of electronics savy to do it. Radio Shack sold a pack of photo cells and there are a few different ones in each pack, they were just a couple of bucks.

A photo cell is basically a resistor that changes value with light. You need to replace your cell with one of the same resistance as the old. In my case, when my cells value was 10K ohms, it tripped the circuit which turned on the lights. The pack that Radio Shack sold had all different resistance values, if you ohm them out with a digital meter, you can figure it out. If yours is shot, you may not be able to measure it. Typically the cell doesn't go bad, its something else, I have seen something in the circuit drift and turn the lights on too early.
 
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Old 11-20-07, 04:47 PM
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Short answer, yes, a photocell is just a fancy switch. As you can see from the previous answers you received, the actual job can be pretty complicated.
 
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Old 11-26-07, 09:17 PM
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Thanks for the info, bought the pack of photocells from radioshack yesterday will try to fix it this weekend and will post the results as soon as we attempt it.
 
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Old 12-28-07, 09:21 PM
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Light now works when temp is below freezing

The solar light works at night when the temps are below freezing. Does this make sense?
 
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Old 12-29-07, 05:08 AM
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Did you buy a photocell or a thermocell? I use thermocells in my chicken house to activate heat lamps below freezing.
 
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Old 12-29-07, 03:06 PM
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We bought photocells but haven't even touched the lamp yet and it started working again once the temp dropped below freezing. Not sure if the cold temps helped to complete a broken circuit or something like that.
 
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Old 12-29-07, 03:28 PM
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It is possible. Electronic shops sometimes freeze portions of a circuit board to find intermittent problems
 
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Old 12-29-07, 04:02 PM
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Interesting. A "cold" solder joint provides intermittent or no connection at the point at which the component is soldered to the board. But solder contracts when cooled.

Maybe it's contracting enough to make a connection when the temp gets low? Try resoldering the connections where the sensor meets the board. Just touch it with the iron long enough to see the solder melt.

Even if you have to replace the sensor, it's better to solder it to the board rather than splicing the leads.
 
 

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