After watching Big Clive's build of a clock a month or three ago, I ordered the fancier version from AliXP (SMT, more matrix display modules), as well as a 7-seg version using discrete RGB 5050 LEDs to light the segments.
https://www.aliexpress.com/item/Large-Inch-Rainbow-Color-Digital-Tube-DS3231-Clock-DIY-kit-with-customizable-colors-Electronic-kit-Gift/32916987930.htmlThe matrix kit arrived first, and I had no problem getting it going. The RGB kit I just completed powered up, but no blue LEDs were turning on.
After redoing a few suspect µC joints, no joy, so I dug deeper. I discovered the 3 LEDs in the 6-pin package are all facing the same way (anodess on one side, cathodes, the other), but the PCB is laid out such that two of the LEDs are in parallel (anodes connected together, ditto cathodes)!!!
This would allow some sort of Charlieplex I assume...IF those two LEDs were facing opposite directions, and my assumption was that the vendor had supplied the wrong LEDs. However, I can't find such "alternating" LEDs anywhere, Ali, Digikey, ...ok...that's all I checked.
Any opinions? Do such LEDs exist (I thought they did)? Is this just another unscrupulous vendor disposing of defective kit?