HUB75 Panel w/ Teensy 4.1 doesn't turn on

I’ve got a Teensy 4.1 hooked up to my SmartLED V5 board and am trying to drive this 64x64 32S matrix. I’ve been able to load up the example sketches to the Teensy without issue, but the matrix doesn’t seem to light up. I’ve uncommented/updated the appropriate lines to configure the example sketches to my setup, verified that the matrix gets 5V power, and verified the ribbon cable connecting the shield to the matrix isn’t broken. Aside from either the matrix or shield being defective, I’m not sure what could be wrong.

Is there a way to check if the SmartLED shield is working properly? I have a digital analyzer I could hook up to the output pins. Also, is there a way I can manually turn on the matrix LEDs to verify the matrix isn’t broken? For example, could I drive one or a combination of pins high to turn a section of LEDs on?

Check this section of the Wiki to see if your panel may need a special mode (FM6126A) or may be unsupported:

You could hook a logic analyzer up and look for activity on all the HUB75 signal pins of the shield. All of them should be toggling for a sketch with active pixels on a 32S panel. On simple panels you can drive OE low and manually clock in pixels, toggling latch at the end to display them to a row, and select a row with the ABCDE pins. Often the panel will display some random pixels just when turned on. If it’s not doing that, then it may be using a chipset that requires initialization first, or may be broken.

My panel uses the FM6124B so it should be supported without needing any special initialization according to the wiki. The panel doesn’t have any random pixels come on when I apply power though, so I suppose that’s a point towards a broken panel.

I’ll hook up the analyzer and manually test the panel to get some more information. Thanks for the guidance!