K8018 Brightness problem after few hours of use

Hello,

I soldered this kit during the holidays and today I gave it a nice place in the house. Plugged it in, everything was OK. After 1 or 2 hours I noticed that allot of LED’s where not bright anymore. It was not touched or moved, it just happened. I have quite some experience with soldering (I also bought and installed the K8200 without any problems). So I’m sure no contact points are bad. So I’m guessing a bad component… After ONLY 1 hour of use… And that for something that expensive… Not happy about it I can tell you…

here is a video to show which LED’s are less bright. I hope velleman can point me in the right direction:

youtube.com/watch?v=eCVWD1GrQ-U

Related to:
viewtopic.php?f=6&t=13169

So what are you saying exactly?

It’s a easy way out to point at the fact that I soldered that chip straight to the board imo… This is something that happens in allot of applications and I’m good at soldering so I did not let it overheat… And like I said it worked perfectly fine for a few hours…

But if you are stating that this unit (IC) is broken, can I get a new one send to me and what would that cost me?

No I’m sorry, I was simply summarizing all information for our technical people, I was not implying anything

Oh ok sorry :wink: It seemed that you pointed out to my mistakes without providing a solution. ok then I’ll wait for a answer. in the video its also clear that it is 3 rows + 1 part of row 4 that does not work. So the technical guys must be able to rout the problem that way, since they know the layout of the board i can only assume.

Hi,

Don’t worry there is nothing wrong with your leds. The two shift registers (the only two SMD components on the mainboard) each have a current controlling ref. resistor. They each control the current through a part of the cube. The fact that one section of your cube is dimmed indicates there is something wrong with one of these resistors. Check the connections/solderjoints on resistor: R1 and R2 also check the values they should both be: 2K2 ohm . Also check the smd solderjoints.

It will most probably be a problem with R1 when I look at your picture.

Ok, thank you very much! This weekend I have acces to a multimeter, then I will check their value.

The SMD, are those the 2 small chips with all the little connectorpoints next to eachother? The ones that you have to solder on top of the board and not through the board (if that makes sense)

Yes exactly, SMD stands for Surface Mount Device, sometimes also referred to as SMT (Surface Mount Technology). The other parts are all through hole which means their leads go through the PCB.

Ok thank you, ill check it this weekend when I have the right equipment and I Will post it here.

Yesterday I Wanted to check the R1 and r2 resistors and the soldering on those two are fine (I could not measure their value yet) then I plugged in the cube just to check and it worked again. It worked for like 3 full hours and then suddenly ALL the LED’s were dimmed and 2 vertical rows were constantly on while all the other LED’s were still doing their animations. I think; this said, that I can say the resistors are ok but it Will be a malfunctioning SMD I guess… I don’t get why it works for hours before acting up. Ill check tonight if it works again or if it is still the same