thanks so much for all the replies...here is a png of what i had wired up:
Your problem might be that you typed in "3.4V" for the voltage when the page says "3.0-3.4V". Putting 3.4V through a LED which came out of the machine as a 3.0V LED is bad. Maybe what happened is that you got two 3.0V LEDs on the same string, if that happens it's easy to get far too much current going through them.
Never run LEDs at their max rating. You gain very little and you run in to problems like this. The numbers on the sheet are maximums
, not recommended working values for 24/7 use.
With designs like this you need to measure
the current going through each chain with a multimeter. Make sure it's <i>less</i> than 80mA. If it's more than 80mA you need a bigger resistor.
It's been working fine for a few hours but i do need this to work for around 7 hours a day for a month. you think it'll be okay?
If you want it reliable, aim at at 75% (ie. 60mA), not 100%. LED output is a curve, not a straight line. Those last few mA gain you a lot more heat than light.
(PS: The datasheet says "Suggestion Using Current 65-75mA"...)