LED diodes out on my Orphek Nilus Unit

pingzing47 · Sep 1, 2020

I have an older Orphek Nilus unit that has 60 - 2 watt leds on two channel control. Recently had 14 leds all in the back row (4 rows, 15 leds in each row) go out. The one led that operates is on one end and happens to be one of the four blue leds on one channel. All of the rest to the left of it are out.
Anybody familiar with what might have gone wrong? Cannot find a circuit diagram so not sure if series, parallel etc circuit. WOuld all 14 be out and need replacement. Have no issue opening up my light and replacing diodes. Could use help in diagnosing the real issue and how to go about this. Thanks

ludnix · Sep 2, 2020

They are likely in series so I would use a voltage meter on continuity test mode which should make the working LEDs light dimly when you use the probes on their positive and negative pads of the led. I use a sharpie and circle bad leds to indicate replacement when you have the soldering iron out.

Let me know if you have any other questions, you will probably be able to see the circuit traces on the board once you remove the led lenses.

blasterman · Sep 2, 2020

These older LED's tend to fail open, so if one goes bad the entire string fails. Doesn't help they tend to use nasty, cheap drivers that have horrid thermal inrush problems.

I just use a battery pack with 2 double AA batterys and test each LED until I find the baddy. You can then just solder a jump around that bad LED and the string will light...until the next one fails.

pingzing47 · Sep 2, 2020

Thanks Attached picture one is just blue channel, second picture with just white channel. And third both channels. LEDs at 20% and it appears the bad row illuminates slightly. If I increase intensity than there is no light that I can see in the bad row. Does this make sense? Can bad led still be the issue or is it the old control box likely cause?

ludnix · Sep 3, 2020

I would continue diagnosing the individual LEDs. The driver can go bad, but it's not uncommon for the string to be dimly lit from a bad LED. When they fail open the whole circuit is dead, but when they fail closed you can get this dimly lit effect or even full brightness on everything except the bad LED. While you can by-pass the LEDs they are super cheap and easy to find on amazon and I would recommend replacing if you have the time. If you by-pass too many LEDs you can cause them to be over-driven because the drivers typically have a minimum voltage you need to reach (by having enough LEDs).

I would start by circling those that don't light at all with the fixture's various settings and then use the multi-meter or battery pack to confirm. Being diodes they won't light if you get the polarity reversed while connecting the battery pack or multi-meter so try the other way around as well. If neither polarity works it's very likely a dead LED and should be replaced or removed.

pingzing47 · Sep 3, 2020

ludnix said:
I would continue diagnosing the individual LEDs. The driver can go bad, but it's not uncommon for the string to be dimly lit from a bad LED. When they fail open the whole circuit is dead, but when they fail closed you can get this dimly lit effect or even full brightness on everything except the bad LED. While you can by-pass the LEDs they are super cheap and easy to find on amazon and I would recommend replacing if you have the time. If you by-pass too many LEDs you can cause them to be over-driven because the drivers typically have a minimum voltage you need to reach (by having enough LEDs).

I would start by circling those that don't light at all with the fixture's various settings and then use the multi-meter or battery pack to confirm. Being diodes they won't light if you get the polarity reversed while connecting the battery pack or multi-meter so try the other way around as well. If neither polarity works it's very likely a dead LED and should be replaced or removed.

I appreciate your response. I opened up the unit and jumped the row of leds and found the bad one - all other lights lit up when jumped. So now it's off to find a replacement led. Thanks again!

pingzing47 · Sep 4, 2020

pingzing47 said:
I appreciate your response. I opened up the unit and jumped the row of leds and found the bad one - all other lights lit up when jumped. So now it's off to find a replacement led. Thanks again!

One final question. Original LEDs are 2 watt. If I can’t find 2 watt can I use 3 watt LEDs?