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Message
Electrician Assistance - LED Lights Not Working on Appliance
Posted on 3/2/22 at 9:18 pm
Posted on 3/2/22 at 9:18 pm
Purchased an “open box” unused vent hood on eBay due to long lead times. Warranty is of course past its window for free parts so I’m having to troubleshoot this and figure it out.
The LEDs worked for 3 months then began to go dim slowly. I assumed this meant the driver was at fault. I tested it in an outlet (120VAC on primary) and it functioned fine (16VDC on secondary).
So when I measure the voltage from the two yellow marks on this diagram, I get 16VDC.
After looking at the diagram I should’ve realized one bad LED could open the circuit since they are wired in series. I tested the resistance of each LED and two of them read “open leads” so I ordered two replacements. Now it doesn’t matter how I plug in any combination of the 6 LEDs - none of them illuminate. Not sure where the issue is. Here’s what one LED looks like:
Maybe there are some electricians here or LED experts who can tell me what specific test I can do or what the issue may be? At an impasse now.
Thanks in advance.
The LEDs worked for 3 months then began to go dim slowly. I assumed this meant the driver was at fault. I tested it in an outlet (120VAC on primary) and it functioned fine (16VDC on secondary).
So when I measure the voltage from the two yellow marks on this diagram, I get 16VDC.
After looking at the diagram I should’ve realized one bad LED could open the circuit since they are wired in series. I tested the resistance of each LED and two of them read “open leads” so I ordered two replacements. Now it doesn’t matter how I plug in any combination of the 6 LEDs - none of them illuminate. Not sure where the issue is. Here’s what one LED looks like:
Maybe there are some electricians here or LED experts who can tell me what specific test I can do or what the issue may be? At an impasse now.
Thanks in advance.
3
Posted on 3/2/22 at 9:50 pm to bapple
Is there a way to retrofit it if you can find the same shaped bulbs in 12v? Had a similar issue with a whirlpool fridge. Half the bulbs were 120v and other half were 12v and the stepdown transformer was part of one of the bulbs. I used led strips and a 12v AC adapter hidden in the roof of the fridge and soldered to the 120v input. Just an idea if you can find same diameter lights in 12v
Posted on 3/2/22 at 10:07 pm to bapple
Based on the schematic info, the LED driver is a constant current power source, where output voltage varies with the number of LED's connected.
Try connecting one LED to the driver with an ammeter in series. If you aren't seeing current in the 6-700 mA range then the driver is bad.
You can also find a constant current LED driver on E-Bay and use that to check your LED's individually.
Try connecting one LED to the driver with an ammeter in series. If you aren't seeing current in the 6-700 mA range then the driver is bad.
You can also find a constant current LED driver on E-Bay and use that to check your LED's individually.
Posted on 3/3/22 at 9:46 am to Unobtanium
quote:
Try connecting one LED to the driver with an ammeter in series. If you aren't seeing current in the 6-700 mA range then the driver is bad.
This is what I’m thinking. Another buddy of mine with electrical expertise said that if the LEDs are all getting dim before they stop working then it’s likely the driver. Even if the driver has voltage on the secondary side when tested with no load doesn’t mean it’ll be able to maintain that voltage when under load.
If this driver is bad I’ll likely buy something off-brand since the factory driver is around $80 and might need to come from overseas (if I could even get it). Any suggestions are welcome.
Posted on 3/3/22 at 11:10 am to bapple
When it comes to LED lights, the drivers suck huge donkey balls.
I wouldnt have even gone as far as you without replacing it first.
We rarely see a bad LED, its almost always the drivers.
I wouldnt have even gone as far as you without replacing it first.
We rarely see a bad LED, its almost always the drivers.
Posted on 3/3/22 at 12:44 pm to kengel2
So... all my years of electrical experience and I made one tiny oversight... DC has polarity and AC doesn’t... whomp whomp.
What likely happened is one LED went bad and I removed the driver to test it. Then after finding out it still works I reinstalled with the polarity reversed on the secondary side of the driver. Man I feel dumb!
One bench test later and here we are.
But there’s no telling if the driver were to go out again so good to have the references if I have to replace the driver. Thanks to everyone for the help!
What likely happened is one LED went bad and I removed the driver to test it. Then after finding out it still works I reinstalled with the polarity reversed on the secondary side of the driver. Man I feel dumb!
One bench test later and here we are. But there’s no telling if the driver were to go out again so good to have the references if I have to replace the driver. Thanks to everyone for the help!
Posted on 3/3/22 at 6:33 pm to bapple
Light Emitting Diode
Glad you got it worked out. I'm sure it was a eureka moment when it hit you.
Glad you got it worked out. I'm sure it was a eureka moment when it hit you.
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