[dentex]

Hello guys!
Sorry if I jump straight here and shoot this question... Usually I don't do like this, but what happened it's kinda weird and I'm badly searching for an answer.

-> Do the LDD drivers burn (break and become unusable, with a "pop" and a bad smell) when they receive the input power but no LED it's attached to them? Because this is what just happened to the only one (of five drivers) I had unconnected to any LED.

I was testing a custom built board:
- Three 700H had LEDs... OK.
- One 1000H had nothing attached, but was shut off (grounding the PWM pin through a resistor)... OK.
- The one left "on" broke (the one with no LEDs attached and with the switch putting the PWM pin to ground in "off" position).

Thanks in advance for any suggestion.

Probably I need to add some details. In this case, if anything is needed, ask please! Thanks again.

 

[jeffkrol]

usually they pop when wired backwards...

LOL _ I'm sure that there's a very, very small percentage of LDD's that fail for reasons other than user error, but the most of the time it is user error. I get PM's from time to time stating that the user's LDD's have blown and the claim is made that it happened due a design defect in one of the PcB's that I've posted here. I always request photos to asses the damage and do a bit of forensic analysis. Every time I've looked at the photos the cause was obvious, either the input wires were crossed, the bottom of the PcB had been shorted to the heat sink, OR the most prevalent- The LDD's were inserted into their holders Backwards! It really should be repeated more often- "check and double check your connections before applying power". It's also a good idea, when working with multiple LDD's, if there are any doubts concerning wiring, proper polarity ect..., only power up one LDD at a time. This way- if something goes wrong, you only smoke one! Not all of them!
Just my .02

http://reefcentral.com/forums/showthread.php?t=2222702&page=84

 

[dentex]

1st of all thanks for answering...

Do you mean the inputs? Swapped?
Well, I used that "channel" on the board previously... it has been wired... and worked... so I really don't understand what happened.

Seeing now the quote and the link... double thanks!

 

[dentex]

Anyway... I hope the problem was a "short" on the bottom of the board... because I had a screwdriver near it... Or tomorrow I'll blow another 1A LDD.

 

[jeffkrol]

most of my power supplies are 48V or larger and have yet to blow an LDD w/ a hot swap or hot fire..though that doesn't mean it isn't possible..

 

[dentex]

Ok. So you exclude that powering the drivers without LEDs can blow them, right? ATM I'm sure of nothing.

 

[mistergreen]

Check the in/out connectors on the LDD with your voltmeter. If it burnt, the circuit may be broken.

 

[dentex]

I suspect it's gone forever. It popped, partially melting on the top side, near the Vin+/dim pins.

I'm almost sure it was correctly inserted. As I said, it just didn't have its LED connected.

 

[mistergreen]

Check your connections. Not having the LEDs connected won't kill it.

 

[dentex]

Ok thank you very much. Tomorrow I'll test the channel with another driver...

Edit: All went Ok...
Incriminated channel worked with a 700H driver and also with a 1000H plus other stuff attached.

[Thanks mod, I'll do it ]