I have installed a sting of LEDs in the bay of my BackShop. They worked perfectly until the last few days when they started to slightly flicker from time to time. It's very subtle, not constant. I swapped out the DC wall wart. That did not fix the problem. Is there something other than replacing the LEDs I can try? Thanks.
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How about a capacitor filter? The wallwart may not have good filtering. Try a 220uf 16V (or greater) cap across the wallwart output.
Gunrunner, I do not know how to do that.
Just connect the capacitor across the power supply outputs. I presume you wired the power supply into the LED's, right?
What's the exact power supply you're using, and what's it rated output?
Here's the power supply. Yes, it's connected directly to my LEDs and the fluorescents in the Backshop. Do I connect it by splicing it on the leads from the power supply? I was thinking of doing it by connecting across the terminal strip that I use to make the connections to the lights. Would that work? By the way, what is that bulge in the power supply lead? It looks like a boa swallowing a pig!
Thanks for your help...
Connecting to the terminal strip will be fine, make sure the positive lead is on the positive connection. The big bar with the minus signs is the negative pole.
The pig in the boa is a ferrite bead to suppress high frequency EMI, you'll see them on many power bricks.
Ed,
I believe the pig that the boa ate is an RF filter. It's a good thing. Secondly, 12v is probably too much voltage for the LED's. You may be prematurely aging them.
John makes an LED driver board that is sold through Henning's that connects to your accessory or track AC and will properly drive the LED's in the building and several other buildings as well.
John, Carl, thanks. I'll try the capacitor and get John's board as I intend to add more LEDs.
If you're using the 12V LED strips, they should work fine on 12V, if you're using something else, we'd have to know the details.
They are 12V LED strips.
John's suggestions should help. Note the polarity of the power supply. The center wire of the barrel jack is + or the plain smooth wire is + if you cut it off.
That 12V power supply is almost certainly a switcher, based on the size and capacity. That being the case, you shouldn't need additional filtering, so I'd suspect maybe the power supply is dying. Have you tried a different 12VDC power supply?
Yes I did try another power supply and it still flickers. The capacitors arrived today. I'm going to connect one tomorrow and hope that stops the flickering. I'll let you know.
Ed,
contact me by email.
bruce
Installed the capacitor and the flickering stopped. Thanks again for your help.
Now I have to find a use for the 29 remaining capacitors that came with the order. 
Add more LED's. 
Yep, that's the plan! also bought 2 of the kits from Henning's so I may be able to light up the neighborhood!
ToledoEd posted:They are 12V LED strips.
I assume these are the strips that come in 3-LED sections. How many sections were you running when the flicker occurred?
Stan, not sure. They run about 16".
I think the most common configuration is the 5cm or 2" section. So you're probably using 8 sections. With a typical current of 20 mA per section, that would be 160 mA total.
I ask because of the minimum load requirement on switching power supplies - your adapter is undoubtedly of that type. I'm not saying yours has this requirement but a common rule-of-thumb is 10% of rated capability. Since your nameplate says 2000 mA, 10% would be 200 mA so you'd be near the minimum possibly explaining the intermittent behavior - and components do age over time and temperature and can change characteristics. It's not like the power supply will blow up or do anything spectacular if you don't load it but it might exhibit instability (flicker?) on its output. In general, adding capacitance to a power supply improves stability. This is just speculation but might connect the dots so to speak.
Stan, so if I understand, you are advising I should not add any further lights to my power supply?
ToledoEd posted:Stan, so if I understand, you are advising I should not add any further lights to my power supply?
No, I think he said that you needed a few more lights to draw enough current to stabilize the transformer output. Add more lights and you shouldn't need the capacitor and have no flicker.
it's an educated guess on his part. Like the Polar Express story, B-E-L-I-E-V-E.
Aahhh. Now I know why my Electrical Engineering mentor in college advised me to pursue a different career. :-)
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