Have 48 led (2 Banks of 24) Shoplight with a standard AC plug into ceiling outlet, controlled by awall switch. Shoplight operated normally for the past year. And then, one day it didn't. It Powers up, but all the LEDs are very dim. Every once in a while, it works normally, but have not been blessed with that for a week now... It is on the garage ceiling, not exposed to moisture... What to check?
Thanks for the suggestions... Solved --- sort of...
Took fixture apart to search for loose connections. Initial inspection showed nothing out of the ordinary. All the bulb connections are of the permanent type, hardwired rather than plugged.
I touched and checked everything I could see at both ends, and pushed to ensure they were all tight. plugged fixture in, and voila, lights.... 10 seconds later, no lights... (actually back to very dim).
Thought perhaps the chain pull switch on fixture may be the culprit, so cut wires and hardwired around the switch. Lights, then no lights.
Tried to pull the circuit board out, thinking there was a wire that had a bad solder joint or something similar, but couldn't remove it. Banged my screwdriver on the metal top of the light, and lights came on... left them on a while, and then eventually turned off the power strip. Turned strip back on, and no lights. Tapped top again with screwdriver, and lights came back on.
So, again tried to remove the circuit board, again unsuccessfully. Stuck my finger in the area circuit board is located, and pressed on all the components and solder joints I could reach, and plugged fixture in again, lights instantly on and stayed on. Powered down and on again the strip down and on again and lights off and on normally. Cussed a bit, and put fixture back together again.
Tested one more time successfully, so reinstalled fixture in garage. Has been working normally since, but recognize this is not necessarily a permanent fix. Have narrowed solution to circuit board, and will wait till next failure before I assault the circuit board again. Believe there is a questionable solder joint or component somewhere on the board.
Again, thanks for all the suggestions.
These lights consist of an LED strip (in your case two strips) and a AC/DC voltage converter referred to as a "driver". Typically when LED drivers fail, they fail completely. The failure you describe is typical of a bad connection - most likely at the LED strip. If you can disassemble it gain access to the strips you should see two "poke in" connectors where the wires go in. I suspect that's where the problem lies.
I just had this happen where 1/2 the LEDs did this in a cheap LED shop light. It turned out that there were two series circuits in the fixture so a failure of one LED would kill half the lights (or severely dim them). I found the defective LED and bypassed it to get the other LEDs working again.