Fail states of LEDs and LED strips
Fail states of semiconductors are in most situations possible to identify source of the issue, however if all conditions and requirements of manufacturer are met, there is normally almost no issues to be expected. LED failure is determined by manufacturer with this graph bellow :
All our products are passing 100Hours burn in test, to ensure none of the LEDs which should fail will fail at your installation.
source : www.osram-os.com
In case you have experienced any of strange behaviour, and you think the installation is made according to manufacturers instructions, we will be happy to assist you to find the root of the issue, which could help us to increase installation robustness and limit some of the failures in future designs to minimum, so all the products will become more harsch installation friendly.
Common mistakes and failures :
- mechanical overstress on LEDs, solder points, or FCB : Whole LED strip segment doesn't work :
do not solder wires on FCB thicker than 0.75mm2 , use only stranded wires , ideally with silicone (soft) insulation. In case you need to connect the LED strips to thicker inlet wires, first reduce the size of wire with short piece of wire.
do not touch the LEDs with anything hard, do not press or apply force, do not twist FCB or bend in place of any components/solder points.
once the LED strip is applied to any surface (double sided sticky tape), installation is done, never remove and re-position the LED strip.
be carefull while handling, installing etc. Always install only in identical width or larger ALU profiles.
common mistake found at installation is that wires from/to LED strips are not mechanically fixed to ALU profile. Prevent from moving with wires to break the LED strips.
How to recognize it? - except visible mechanical damages to LEDs or FCB, LEDs can be broken which can be hard to spot (sometimes they can be lit when gently pressed by finger). Whole LED segment will not work. Failure can be not visible imidiately.
- issues related to soldering station or soldering temperature : First LED in segment next to solder point doesnt work , segment might work :
always use micro soldering station with temperature controll, do not solder over 300°C for 10seconds. Always ensure the LEDs when soldering are at least 24hours in dry and interior temperature (thermal stress can damage LED, or thermal stress can cause a penetrated water trapped inside the LED package to quickly vapour, thus break the package. In case you need to carry on the soldering process in colds / exterior / damp area, preheat the soldered end with heatgun and low temperature of 70-100°C for 1-2 minute to allow the LED water slowly vapour and LED will not get thermall stress)
- issues related to ESD - Electrostatic discharge : it is very hard to find, because they can take some time to manifest (100's of hours)
be aware of handling the LED strips and installation without ESD safe conditions.
always do ground the body of ALU profile too (to prevent ESD discharge to jump to LEDs inside when manual touch with ESD ocurs)
failure of such damaged LED is normally determined that LED will not work or will be much less brighter AND the most likely that the rest of the LEDs in segment will work OK. This kind of ESD discharge normally penetrates the PN junction of LED, which will degrade brightness of particular LED.
- LED overcurrent : affected LED will have tiny black dot inside, whole segment will not work :
such bahaviour is normally not expected as all our designs do contain constant current drivers. In some specific installation situations this constant current driver can be by-passed (accidental pressing with screwdriver, or metal parts/solder residues will short circuit the driver, etc)
Affected LED should have black tiny dot inside, whole segment will not work. This failure doesnt have to be visible immediately.
- Reverse polarity :
most of our designs contain reverse polarity protection, but some older designs might not have sufficent space for all components, thus might be not reverse voltage protected.
In case your installation does contain any failure, we will be happy to assist you with diagnosing what is the root of the issue, however we will need the whole portion of LED strip to be delivered with original ALU profile to us. Un-taping the LED strip from ALU profile will damage the whole LED strip, and will block any further diagnostics.
Our RnD dept. contains alot special devices and meters to measure and check the LED fail state. In case we need, we can send the portion of LED strip to OSRAM RnD dept. for in-depth diagnostics on almost molecular level.
In case your installation does conatin any failure and you just want the installation to work, you have the following options :
send us the faulty LED lines (including ALU profiles), we will replace the faulty LEDs/segments with exact and new, will run a burn in test for you. You just pay for the transport costs.
send us a photography of faulty LED, information about product and its BIN, and we will ship you required number of new segments with identical spectral properties. You just pay for the transport costs, and you will need to replace the segments on your site.
We understand that sometimes it is hard to keep all required conditions while installing any quality producst in high places, facades, or places which are easyly not reached. We are here to help you to carry the whole project to 100% state. We will be happy to teach and show you the mistakes you did, so you will be more carefull and will not repeat it next time.