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Repairing cabinet LED lighting with stock power supply

hcrawford

Nov 25, 2022
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Nov 25, 2022
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Hi – About 10 years ago we remodeled our kitchen, putting in 3 sets of cabinets with LED cabinet lighting. The installer had put in 120V sockets above each set of cabinets, and a lighting set was plugged into each one, each set consisting of 3 LED lights and a transformer. Over time, the lights started to dim. Long story short, I cut into the top of each cabinet, finding the power supply, each of which had 3 10V x 350 mA outputs, one for each LED light.

The original transformer (CDC-1Wx3 Class 2 Transformer for LED Lamp) was so longer available, so I purchased 3 power supplies, each one with 10V x 1A output, and planning to run the 3 lights in parallel. But when I powered up the first circuit, the lights started strobing, about 1 pulse per second. I’m guessing that too much current is going through the circuit and overdriving the LEDs, so I put a variable resistor (2W) in series with the three lights. Adjusting the variable resistor to get optimal light output without strobing, I saw that I needed a 7-ohm resistor in the circuit (keeping the variable resistor in place isn’t really an option, as it was getting pretty hot).

I might be able to cobble together some 10W resistors to make a 7-ohm resistor, but just to ask, am I going down the right path?

Replacing the entire system would be difficult as it would require taking down the entire cabinet attached to the ceiling and wall to get to the wires. So I’m hoping for a simple fix.
 

kellys_eye

Jun 25, 2010
5,282
Joined
Jun 25, 2010
Messages
5,282
Over time, the lights started to dim.
Replace the lights. They may be 'multi-chip' devices and a defective LED in any one of them will cause the over-current situation resulting in the strobing you see.

Cabinets lighting is so cheap these days it's often not worth trying to fix defective versions but get a whole set with matching transformer and replacing the lot wholesale is probably cost-effective and a lot safer.
 
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