Mini Tide malfunction

[Swymer]

I have a Nano Box Mini Tide plus M that I have had since 2016. Was adjusting the spectrum to the SPS+ recommended on this site and was able to set all the channels to the correct % except channel 3 which is violet. The problem is that the violet led can't be turned up past the first increment which is less than 1% intensity. I'm pretty handy and can solder but have no idea where the problem lies. Seems that it is either the driver or a bad channel on the Storm Controller, because the violet led does come on a little bit.  Any ideas?  And in case it's more than I can tackle myself, does anyone know of a good source for LED electronics repair? 

[rsucre]

The only thing that comes to my mind is testing the channel with a voltmeter and see if the voltage ramps up as you adjust it. Measure at the controller, then at the led array solder pads to see if it drops. Perhaps a cable is bad?

[Swymer]

Should I set the voltmeter to AC or DC?  And any idea which pins on the controller are for channel 3?  The wire colors from left to right: blue, white, brown, orange, green, yellow. And the black wire located directly beneath the blue wire is the ground for all the channels?

[Swymer]

The voltage from the controller on channel 3 is .04 volts DC when set to the lowest intensity, and 4.99 volts DC when turned all the way up to 255. I guess that means the controller is working properly.

 

Now I'm not sure I measured the voltage properly at the led pad but when the controller was set to the lowest intensity it read 23.3 volts DC and when the controller was turned to full intensity the meter read 25 volts. Shouldn't I be getting 4.99 volts if I'm touching the correct solder pads? I probed the pads with the orange and purple wires. I didn't see anything that looked like a GND but that's probably what needs to be probed along with either the purple or orange wire. Anybody know?