Trouble shooting with ELN-60-48D drivers for electrical gurus

[SoFloReefer]

I have a DIY fixture with two ELN-60-48D drivers, each running 14 Cree XP series leds. Lately it has been shutting off on its own.
It has one 10v, 500mA wall transformer wired in parallel to one 12v, 300mA fan, and to two potentiometers, one for each dimming circuit. When it shuts off, both ballasts shut off simultaneously. They ramp down as if the voltage on the dimming circuit drops to 0. The fan continues to run after the ballasts shut down. If I touch the potentiometer for the ballast which controls the blue leds, the fixture lights up but then ramps down then off.
Before I tear into the wiring to find the problem, maybe someone can steer me in the right direction.
I don't believe that the problem is with the ballasts. I think that the wall transformer is failing. The only thing that is throwing me is that the fan continues to run after the lights shut off. The problem happens intermittently but is happening more frequently.

[SoFloReefer]

I disassembled the dimming circuit and tested each component. I now believe that the problem is with the ballasts. Normally when the 10k pot is at full resistance, the lights shut off. Now the lights will not shut off but only dim; and when I test the voltage on the dimming circuit (DIM+, blue and DIM-, white) it only drops to 3.13v on both ballasts when it should be near zero. If I unhook the 10v power supply, it then shuts off. I am wondering if I damaged both of the dimming circuits in the ballasts by running a fan off of the same circuit.

[2Quills]

Did you isolate each driver separately and test them without the potentiometers hooked up? Try hooking the + and - wires of your 10v walwart to the + and - dimming wires on one driver at a time then take a current reading for the output of the driver.

You got some kind of sketch or schematic of how your pots are hooked up with the drivers and the fan?

[kcress]

Two things:

1) You are expressly forbidden to send 12VDC to those ballasts. If you do they're toast. Some wallwarts are not regulated. So a 10V one may actually be 12V or 13 or 15 if the load is not the fully rated one on the label. So you need to check that.

2) Pots have a power rating. Doing the wrong thing with them can certainly damage the pot. It can often be the wiper point that fails first. Hence moving it to other positions might not help anything.

You make sure you're running the pots below their wattage. Since touching the pot causes an immediate change in system that's the place to look.

[kcress]

2Quills you cross posting sneak!!
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:lmao:

[2Quills]

Good point. Test the walwart first.

Sneaky is as sneaky does. :P

[SoFloReefer]

Thanks for the responses. The wall wart is from Rapidled and tests at near 10.05 volts regardless of load. I believe it is regulated. I isolated each ballast and both are still exhibiting the same behavior. The dimming circuit will go from 3.13v to 10.05 volts when a 10k pot is hooked up. I tested resistance on both of the 10k pots and both seem fine. I also used other 10k pots and had the same results. The power rating for these pots are 0.2 watts. When I remove the pot from the circuit and directly hook up the wall wart to the ballast, it gets the full 10.05 volts and runs at full brightness. How can the voltage on the ballast dimming circuit (the Blue+ and White- wires) be 3.13 volts with 10k of resistance? There must be some kind of damage on both ballasts. I'm going to open them up and take a look.

I opened both ballasts and I don't see any obvious damage such as burned joints or leaking caps.

[2Quills]

I just can't see how it would be the drivers. If the pots are functioning correctly then there should be 0 volts coming from the wiper leg when turned all the way down.

Disconnect one of the drivers from it's pot, connect your test leads to the + and - dimming wires on the driver. Plug the driver in and see if you get any voltage readings coming from your dimming wires. With the ELN's you shouldn't see any voltage at all.

You said that you checked ohms on the pots and you saw them ramp and and down all the way from 0-10k?

[SoFloReefer]

I just can't see how it would be the drivers. If the pots are functioning correctly then there should be 0 volts coming from the wiper leg when turned all the way down.

Disconnect one of the drivers from it's pot, connect your test leads to the + and - dimming wires on the driver. Plug the driver in and see if you get any voltage readings coming from your dimming wires. With the ELN's you shouldn't see any voltage at all.

You said that you checked ohms on the pots and you saw them ramp and and down all the way from 0-10k?

I checked both pots and they ramp up and down from 0 to 10k ohms. The dimming wires on both drivers read about -1.3v (meaning the polarity is reversed) when nothing is connected. They do shut off when nothing is connected. I hooked up a 10k ohm resistor in the dimming circuit to eliminate the pots as the problem and I had the same result. The lights stay lit and I'm reading 3.3v across the dimming circuit. :headwally:

[2Quills]

Yeah, something definitely doesn't sound kosher with the drivers then.

[SoFloReefer]

This sucks, I really don't want to spend $60 on new drivers. Maybe I'll look at the Invertronics.

I wonder what would cause both drivers to fail in the same way. Crazy.