Power Supply Question

I recently purchased a power supply for my Traktor Kontrol S4 MK1. Is there any way to test that the power supply is actually working? If I power the unit on with just the power supply plugged in and no USB cable, nothing happens - no lights, nothing.

If i connect the unit via USB and power supply, nothing happens when I plug the power supply in / unplug it while running from USB. I was under the impression the headphone cue might be louder and the LEDs would be brighter with the power supply. I'm thinking the power adapter might be faulty. I can hardly see some of the lights on the buttons, and I have the software settings for brightness cranked.

I purchased the power adapter from Amazon. The seller is Native Instruments, and it came in official NI packaging. Here's a link, if they are allowed:

It doesn't specify if it is for the MK1 or MK2, but the date first avilable on Amazon was June, 2011, which leads me to believe it is for MK1 (and MK2 if they use the same power adapter).

Is there any history of the power unit inside the actual controller going bad? I have no other device around to test this power supply on.

Thanks for any input.

 

Well here's an update - I purchased a second power adapter from NI to keep isolating the issue. The second one does not power the unit on either. It still powers on via USB, but I can unplug and plug the power adapter in while running it on USB and there is zero difference in headphone cue volume or LED brightness. The wall socket is tested and working. Unless I got two bad adapters, there must be something wrong with the internal power supply of the unit. Has anyone come across this issue before?