Assistance please with a flood light problem

Thread Starter


Joined Feb 3, 2013
I have a conventional yard flood light that is now giving me a problem. The problem is that the timer that can be set to determine the amount of time that the light stays on is not working correctly all of the time.
I can have the light connected and it works well for 5 days then for some reason the light does not shut off and stays on all night. When I manual shut off the light (cut the power) then turn the power back on it will function correctly for a few days and then will not shut off again. All other functions are working OK.

I am hoping that some one might be able to start me off in getting this light working well again.

In the interest of providing additional information which might be of help I have included the following as well as an image of the flood light!

This unit contains three small pots which can be set to ones requirements.
The electronics is provided on 2-small boards, one for the AC-DC conversion the other the circuitry for the flood light.

I removed the electronics from the light and it consists of the following:
A power supply board which contains:
A relay switch 7amps AC 250 Volts, as well as the expected 4 power supply diodes and 3 large capacitors, a transistor and a few resisters.

The electronics board contain the following
1-LM432N IC
1- IR Detector
1- Photo resister
3 Pots for setting the sensitivity of the IFR Sensor, sensitivity to the Photo resister and finally a Pot for setting the Light – On duration.
( It is here that I have the problem).

I thank you in advance for any assistance you might be able to provide.



Joined Nov 30, 2010
My first impression is, squirt some contact cleaner in the pots. A bit of dirt and they will not conduct.

Thread Starter


Joined Feb 3, 2013
Thank you all for the response!

I will try and answer all of the questions asked and or provide more information.

The unit was purchased by me from a supplier here in Thailand. The unit is made here or in China.

I am providing two additional images which I hope helps. I think that you can see that the photosenser is a Photo resister


I had thought that the problem could be a cold solder joint or an issue with the timing pot, but as I am a bit of a newbie I wanted to ask for assistance.
The comment about using a contact cleaner to try and clean the Pots is a good one. I have checked all of the solder points and they appear fine.

I hope that this information is of use and thank you again for your responses.


Joined Apr 28, 2012
Cheap relay maybe. The contacts fry together. As a halogen lamp has very low cold resistance this is likely.

Replace with contactless relay module. Or high quality relay.

I saw this behaviour for a small motor (which of course has a high startup current). After some months, it would stay on sometimes.


Joined Aug 30, 2007
Is this light controlled from a light switch? There are some out there that let you bypass the motion detector by flipping the switch on/off a couple of times giving the results you describe.


Joined Jan 10, 2012
I agree with post #6. I was gonna suggest this as the problem as I have the same problem with a motion controlled light. My problem shows up when it gets cold, which led me to suspect the E-M relay.

Thread Starter


Joined Feb 3, 2013
I want to thank every one for taking the time to reply to this thread.
After much testing I seem to have found and corrected the problem with the flood light.
The problem was a dirty pot, I used a contact cleaner and the light works well now.

Thanks again to all!