Led Gurus Please Help

[Vonkins]

Ive got 4 cxb3590s on a 36x6 heatsink pushed by hlg240h1750b, dimmed of course. I run 5 bars like this. One of my bars went out on me. I assumed it was my driver, so i bought a new one. Nothing changed, the lights still didnt come. Correct me if im wrong, but these cobs have to be run in pairs and run in series with the driver i have. Im reading 142.5 five volts at the light bar when my positve and negative are taken loose off each end. So i know im getting power to the light bar. Can i just test 2 cobs at a time then determine from there which one is bad? For example test the two on the right then the two on the left. Which ever set doesnt come on then its one of those two cobs that have failed right?

 

[G gnome]

@Toaster79

 

[Toaster79]

Take insulated tweezers and make a bridge over each cob (+ and - is to be connected). Basically bypassing it in the circuit. This way you exclude each cob to find the bad one. You can also use a piece of wire, just make sure youre not touching anything bare/non insulated.

 

[heisen]

Check your dimmer also,I just cut mine off and tied the two wires together.had 2 dimmers malfunction.

 

[Toaster79]

Check your dimmer also,I just cut mine off and tied the two wires together.had 2 dimmers malfunction.

Faulty dimmer won't prevent the lights to go on, it will just keep them dimmed or full power. His setup doesn't even light up.

 

[Mr.jiujitsu]

Faulty dimmer won't prevent the lights to go on, it will just keep them dimmed or full power. His setup doesn't even light up.

Potentiometers do die. In industrial equipment I have seen them fail from cheap spring style contact that’s made. Let’s say a handful over 16 years of experience... I just had one malfunction out of the box but only the display output was incorrect.

 

[heisen]

Faulty dimmer won't prevent the lights to go on, it will just keep them dimmed or full power. His setup doesn't even light up.

Mine was bad and my light output was half of what it was supposed to be.i couldnt tell looking at it.only way I found out I had some slow growth on one side of the scrog.i used the lux meter on my phone and it was half of the other light bars.
I was just throwing that out there.
He definitely has a bad cob or short somewhere.

 

[Toaster79]

Potentiometers do die. In industrial equipment I have seen them fail from cheap spring style contact that’s made. Let’s say a handful over 16 years of experience... I just had one malfunction out of the box but only the display output was incorrect.

Mine was bad and my light output was half of what it was supposed to be.i couldnt tell looking at it.only way I found out I had some slow growth on one side of the scrog.i used the lux meter on my phone and it was half of the other light bars.
I was just throwing that out there.
He definitely has a bad cob or short somewhere.

I know potentiometers do die or come faulty out of the box but that's not the case here. His light won't come on but he's measuring 142.5V on an open circuit (should actually be 146V). So the driver is putting out what it can. Potentiometer has nothing to do with this problem here.

 

[Mr.jiujitsu]

I know potentiometers do die or come faulty out of the box but that's not the case here. His light won't come on but he's measuring 142.5V on an open circuit (should actually be 146V). So the driver is putting out what it can. Potentiometer has nothing to do with this problem here.

I agree

 

[heisen]

I know potentiometers do die or come faulty out of the box but that's not the case here. His light won't come on but he's measuring 142.5V on an open circuit (should actually be 146V). So the driver is putting out what it can. Potentiometer has nothing to do with this problem here.

I know that,I was just saying for him to check it cause I had issues with mine.sounds like he has a short or a bad cob.i agree with what u said.
Could a faulty pot cause one of the cobs to ho bad?

 

[Toaster79]

I know that,I was just saying for him to check it cause I had issues with mine.sounds like he has a short or a bad cob.i agree with what u said.
Could a faulty pot cause one of the cobs to ho bad?

Faulty pot only has influence on the drivers output. In this case with 4 3590's driver tops out at max voltage at full power (theoretically) as it puts out 143V max which means each cob would get 35.75V. If we look at 3590 datasheet, at 1750mA and 25°C the cob would pull 35.5V so this should suffice

As temp rises, Vf drops so driver isn't running at 100% anymore.

I could imagine one or two or maybe even all four cobs in series have much higher Vf like let's say 39V and the driver couldn't provide enough voltage to light them up but that would be very unlikely.

 

[heisen]

i would see my lights flicker from time to time,thought i had a short but it wwasnt that,As soon as i cut the pot off and taped the wires everything went back to normal.

 

[Mr.jiujitsu]

i would see my lights flicker from time to time,thought i had a short but it wwasnt that,As soon as i cut the pot off and taped the wires everything went back to normal.

I have taken pots apart that acted like that and bent the “spring” connection so proper contact was made and everything was good. It was for a piece of equipment that ground bearings for aerospace, not lights, but regardless the components function on the same mannor. I have work on equipment that was built durring the start of the Cold War up to water filtration/production equipment currently being used to make biophysical products. That being said when my last pot died, I replaced it lol fuck taking that cheap shit apart, my personal time is worth more than replacing it lol

 

[Vonkins]

I know potentiometers do die or come faulty out of the box but that's not the case here. His light won't come on but he's measuring 142.5V on an open circuit (should actually be 146V). So the driver is putting out what it can. Potentiometer has nothing to do with this problem here.

My driver output is 143 volts according to the print on the driver. I also had it dimmed some to if that affects voltage but i think amperage affects the brightness and not voltage.

 

[Toaster79]

My driver output is 143 volts according to the print on the driver. I also had it dimmed some to if that affects voltage but i think amperage affects the brightness and not voltage.

You can control power through a led two ways. With constant current and constant voltage. Have a look at that graph I posted and tell me what happens when you apply heat (power) to your semiconductor. With constant current, forward voltage will drop as temperature rises and your cob will pull less power. At constant voltage, current through your led will rise as temperature rises and if the driver can supply enough current you'll experience a chain reaction with not so happy ending. So voltage and current are closely related. Also the temperature plays a big role. If you can keep all three in control you'll have little problems for the next 10 years.

Now let's get back to your problem. Did you try to diagnose a faulty cob yet?

 

[Toaster79]

My driver output is 143 volts according to the print on the driver. I also had it dimmed some to if that affects voltage but i think amperage affects the brightness and not voltage.

Your driver operates in constant current mode in the range between 71V and 143V with a load. With no load you should get 146V max on the output (open circuit). If you had it dimmed down then 142.5V makes sense measuring open circuit.

 

[Vonkins]

You can control power through a led two ways. With constant current and constant voltage. Have a look at that graph I posted and tell me what happens when you apply heat (power) to your semiconductor. With constant current, forward voltage will drop as temperature rises and your cob will pull less power. At constant voltage, current through your led will rise as temperature rises and if the driver can supply enough current you'll experience a chain reaction with not so happy ending. So voltage and current are closely related. Also the temperature plays a big role. If you can keep all three in control you'll have little problems for the next 10 years.

Now let's get back to your problem. Did you try to diagnose a faulty cob yet?

Yes but my dumbass was so engulfed in proving i had a bad cob or holder, that i hooked them up in pairs. When i tested the two middle cobs the right one came on. I added my last cob on the left cut the power back on and that sme cob came on then went off after about 30 seconds. Now like i said i completely forgot about polarity with my adhd ass. So tonight i will hook them up again with the correct polarity and see what happens

 

[Vonkins]

This is with the middle 2 cobs hooked up last night. Polarity could be wrong. Can u see if they r pilarity correct. If the 1st cob is hooked up correct but u screw up the 2nd cobs polarity will the 1st one still come on.

 

[Vonkins]

This is with the middle 2 cobs hooked up last night. Polarity could be wrong. Can u see if they r pilarity correct. If the 1st cob is hooked up correct but u screw up the 2nd cobs polarity will the 1st one still come on.

Polarity is definitely wrong!!!!

 

[Toaster79]

Yes but my dumbass was so engulfed in proving i had a bad cob or holder, that i hooked them up in pairs. When i tested the two middle cobs the right one came on. I added my last cob on the left cut the power back on and that sme cob came on then went off after about 30 seconds. Now like i said i completely forgot about polarity with my adhd ass. So tonight i will hook them up again with the correct polarity and see what happens

That could be your problem. Wrong hooked cob. Your driver has reverse polarity protection but looks like it's not kicking in right away but let's current leaking throug your reversed cob which might indicate that cob took some damage.