8018B 5x5x5 led cube not working

After a lot of soldering I assembled the complete unit. However it does not work. If I connect to PC via USB port the red led is burning. If I connect 9 V powersupply the red light is not burning. Loading a pattern via the software into the cube does not give any reaction, the blue leds do not blink.
On the pcb there are quite some measuring points. Is there a way to use these measuring points for fault finding?

Dear @Rwin66 ,

It’s normal if you only connect USB cable, the red LED LD1 lights up.
But then the LEDs get no voltage.

To make the LEDs light up, the 9V DC (min. 300mA) adapter must be connected anyway.
Normally the Random pattern (demo code) starts then, which lights the LEDs in pattern sequence.

In other words. you always need a 9V power supply to make it work. The LEDs are not powered via USB. Only connected via USB, IC1, 2 ,3 is powered and not the LEDs.

Both the CPU (PIC) IC1 (yellow +5VPIC) and the LEDS +V5 (green) are controlled via the 9V adapter.
See image below.

If LEDs do not light up when plugging in the 9V adaptor:

  • Check the polarity of the LEDs (possibly polarized incorrectly).
  • Possibly Driver IC2 and 3 defective.

See circuit diagram page 15:

Best Regards,
Velleman Support

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