Help with intermittent fault on a CXB3590 panel

Well I am waiting on some solid core wire & 10amp cable connectors to be delivered. When that happens, I am essentially going to re-wire the whole thing & replace the potentiometer. Bit of a ball ache but cheaper than a replacement driver & safer than a fire caused by a short! Touch wood, the problem has not re-occurred since I posted this thread.

I did also think that this is an odd one. I learnt most of my building skills from threads on forums & YouTube videos so I can’t really call myself any sort of expert but (correct me if I’m wrong here) I thought with series wiring if there was a problem with a cob or wiring in the circuit, none would light up. The last 2 must be passing current in order for the first 2 to light up.

I was originally leaning towards the driver failing & not being capable of driving all 4 cobs but, since reading all the reply’s I have realised it could actually be quite a few other things.

This may be one of those situations where I have to do a full re-wire & never find out exactly what the cause was. I’ll update when I know more. Again thanks to everyone for their help trying to get to the bottom of this.

Don't use cheap pots, they might work for a short while, but they will either drift or the middle pin loses good contact with the resistive track in short order.
Use Alps, Bournes or Vishay.

Any chance you could do a simple sketch of what you have in front of you as the light is now.

I must admit I have only used the cheap ones from *bay to date. I didn't really know which brands to look for. I can pick up some Vishay on the bay.

Sketch wise what are you specifically looking to see?

There is a photo of the panel on my first post that I took when the panel last displayed the fault.

Are you wanting to see the wiring on the back of the panel?

kushedy said:

did also think that this is an odd one. I learnt most of my building skills from threads on forums & YouTube videos so I can’t really call myself any sort of expert but (correct me if I’m wrong here) I thought with series wiring if there was a problem with a cob or wiring in the circuit, none would light up. The last 2 must be passing current in order for the first 2 to light up.

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Yes, you are correct - current must be passing through/by/around them somehow. Something making contact somewhere where it shouldn't. I would probe with a meter and see if I could find anything unusual. Where in the string are those two COB's?

The last 2 cobs. If you have a look at the photo in the first post you should be able to see that the cob that is lit on the left has a red wire going in one side. That is the positive in from the drivers positive, start of the string. The wiring then runs to the next cob cob on the right which is also on. The wireing then travels from that cob to the cob directly opposite it which is not on & then over to the cob on the left which is also not on. The negative from that last cob on the left then goes off to the negative driver cable.
They are still operating as normal today touch wood. I'm still waiting on some parts that should have been here by now in order to re-wire the panel.

could you not twist dim+ and dim- together and it be full dimmed wattage (50% iirc)? i have a hlg 185 c1400b and if you twist those together, it goes to fill dimm. if all 4 work, it's the pot. hope this helps, i had a faulty pot and it was weird acting, but not the same exact problem you described.

kushedy said:

Sketch wise what are you specifically looking to see?

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THe + and - supply, and how you connected it to the LEDs in terms of + and -

even a clear picture of the wiring showing where leads leave one component and enter the other (usually pics do better than sketches because you might have sketched it correctly and executed the wiring dress incorrectly)

kushedy said:

The last 2 cobs. If you have a look at the photo in the first post you should be able to see that the cob that is lit on the left has a red wire going in one side. That is the positive in from the drivers positive, start of the string. The wiring then runs to the next cob cob on the right which is also on. The wireing then travels from that cob to the cob directly opposite it which is not on & then over to the cob on the left which is also not on. The negative from that last cob on the left then goes off to the negative driver cable.
They are still operating as normal today touch wood. I'm still waiting on some parts that should have been here by now in order to re-wire the panel.

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When the two were off, did the two that were on seem brighter or dimmer than usual?

@nonamedman420 thanks I'll give that try if the fault re-occurs before my new potentiometers arrive.

@ANC & @CannaBruh I'll take a few more pictures at lights on. Easier option for me but in the meantime to hopefully give you a little more info the positive lead from the driver is attached to the positive of the first cob in the string (ideal solderless holders on cobs). The negative lead from the driver goes to the negative of the last cob in the string.
So essentially if you laid them out straight in a row it would look like 4 cobs with 1 wire running through all of them. I could be wrong here but I think you guys are concerned that the cobs have not been wired in series. I'll be the first to admit that I am not a DIY god but wiring in series is something even I can manage but I will have some pictures for you within the next 24hrs.

@nfhiggs to be honest it’s been nearly a week since the last time this happened & I have the memory of a gold fish so I cannot really remember. What I can remember which may or may not be of help is that this panel is on a plug-in wattage meter. When all 4 cobs were active the dimmer was set for the panel to run at about 150w total draw. When only 2 cobs were lit the wattage meter was showing a power draw of 70-80w total. I could dim the 2 lit cobs down further or up to around 140-150w. It almost looked like the driver could not see the last 2 cobs.

I think this is either the driver or like some of you have suggested some sort of short in the wiring of the last 2 cobs. All 4 cobs came on again last night so again nothing to use to fault find at the moment.

@kushedv i have no experience with the ideal solderless holders, but are they set up so you cannot accidentally install the cob backwards (i.e. accidentally swapping the + and - side of the cob, so it looks like it's wired correctly from the outside but actually hooked up wrong) i personally don't think it EVER would have worked correctly if the + and - were swapped, but i bought a chinese cob and driver combo as my 1st foray into cobs, and i must admit hooked it up backwards, but only because the driver wasn't labeled correctly and my multimeter shit the bed. it worked both ways, don't ask me how. also, swapping acl for acn and it worked too. weird as hell. doubt anything i said helps, but you never know. good luck my friend!

If the series circuit works where only 2 emitters are lighting, the other two must be forward biased or shorted to pass current for the lit two, that's the thing that is puzzling, that 2 would light (implies current flow) but we are puzzled as the 2 not lit must be forward biased (light up) to pass that current, or they are dead short, or other wiring muckery.

If polarity were flipped you'd have reverse biased the diode array and the thing should never pass current sans a reverse over voltage causing a breakdown of the device.

Good luck hope you get it worked out.

@nonamedman420 I'll have a look at next lights on but yeah I doubt they would have worked as long as they have if one of them was wired back to front.

@CannaBruh unfortunately a lot of what you said went over my head.doh!
Fingers crossed once I re-wire it doesn't happen again.

I have attached another image. This is the top side of the panel. You are not going to be able to clearly see the wiring as it has been pushed in between the fins of the heatsink. As you can see I have highlighted the positive in & the negative out.
Essentially the circuit starts with the positive cable running to the left under the fan, through a hole in the heat-sink & into the first cob. The next wire comes out of the first cobs negative, up through a hole in the heatsink & then tracks across to the right where it goes back through the heatsink to the next cob where it is wired into the positive. The next wire comes out of cob 2's negative & up through another hole in the heatsink where it then travels across the panel to the cob on the far side of the panel. The big yellow line in a u-shape shows the course of the wire. Anyway still no repeat of the issue at this point.

@kushedv please let us know if you figure out the problem, as i'm sure someone else could be helped if in a similar situation. good luck my friend!

in a series string if 1 goes out non of the should light up i believe so the fact 2 are lit makes me think they might not be wired correctly . also if not you could have a short do you have the light grounded , is there any small wires not quite in the connectors that are or could touch the metal holders or the case ?? (if this is the case its really dangerous ) i beleave you can test using a multi meter

I don't know about cobs but most of my single diodes on my pcbs with pass the voltage through them even when they don't work. And they are all in series.

jarvild said:

I don't know about cobs but most of my single diodes on my pcbs with pass the voltage through them even when they don't work. And they are all in series.

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If diodes have failed short they can pass the current but at some small or no voltage drop, if the pn junction of the diode is not damaged it should only pass current when forward biased (lit.)

Well that may well be the case, all I'm saying is what I'm experienced with. My 4x4 up pcbs have every blue diode not functioning but yet everything down the line still operates besides the blue diodes.

jarvild said:

Well that may well be the case, all I'm saying is what I'm experienced with. My 4x4 up pcbs have every blue diode not functioning but yet everything down the line still operates besides the blue diodes.

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I was merely trying to explain the mechanics behind the what and why that may be is all I'm sure someone eventually will dig deep enough and find a root cause for why you guys see what you are.