P3-6432-2121-16S-D1.0 panels don't work at all


I got a free batch of those, as they were returned by people who weren’t able to use them either.

I can confirm that they are not compatible with normal HUB75 panels. I used 2 teensy programmed to work with regular HUB75 panels and they worked fine.

Then I plugged them in multiple of those new panels, and nothing lit up. I made sure I was connected to the “IN” connector, but nothing lit up.

I then removed the HUB75 connector and rubbed my finger over the connector to create random signals, and got LEDs to light up.


  • The panel power and LEDs work
  • They are not compatible at all with HUB75 signalling as output by SmartMatrix.

I know some panels move pixels around in annoying ways, but are there known panels that don’t even light up at all?



Have a picture of the back?

Could be one of these panels which the current version of SmartMatrix Library and the SmartLED Shield can’t support: https://github.com/pixelmatix/SmartMatrix/issues/49

It’s possible the ESP32 platform could support these panels with no external latch and GPIO driving all signals. It’s an extremely low priority for me to add support for these panels, hopefully the suppliers don’t all switch to this new method of addressing.


@Louis I didn’t realize it was also an AB address line problem since it was only P3 and not P2, but I guess it makes sense that it would be the same problem.

mentions AB for 64x64 1:32 when this one is 64x32 1:16, but that doesn’t mean it’s not using AB anyway.

Pictures: Sure, there you go. By the way, smartmatrix v4 is starting to be a bit too big with a teensy 3.6. It would fit better if the teensy were offset up a bit. I did use a smaller teensy 3.1 to make it fit and make sure it wasn’t a bad connection problem


Are there any labels under the SmartLED Shield, that would give a hint as to if this is in fact an AB panel?


You can clip the extra pins off the Teensy 3.6, or mount them on top, or with right angle pins like the instructions mention. Of course that’s no good if you want to use the Teensy 3.6 with another board that needs the pins pointing straight down


For the pins, yes, I can bend or clip them, I just wanted to show the conflict on newer smaller panels. It’s true that there isn’t much that can be done with the shield, because if you offset the teensy up, it’ll hit in the other direction.

For the wiring, I got this back from the seller. Honestly it sounds like a regular ABCD panel, no idea why it doesn’t work. I asked the seller to try some of those panels to see if they work for them. Maybe it’s a batch of defective ones, although I have 15 of them with different white labels and numbers, and some are yellow and apparently a different batch. None of them work.
At this point, I’ll see what they say, but the problem may be elsewhere.

        |our buyer share his experience about the wiring label.|
        |here is details,                                      |
        |1 - 24                                                |
        |2 - 25                                                |
        |3 - 26                                                |
        |4 - Ground                                            |
        |5 - 27                                                |
        |6 - 28                                                |
        |7 - 29                                                |
        |8 - Ground                                            |
        |9 - A0                                                |
        |10 - A1                                               |
        |11 - A2                                               |
        |12 - A3                                               |
        |13 - D10                                              |
        |14 - D9                                               |
        |15 - D11                                              |
        |16 - Ground                                           |
        |                                                      |
        |Hope it helpful for you,


Check the controller chip that install the LED panel, if are ICN2038S or FM6126, those are not compatible Smartmatrix because these chips require three clock pulses by Latch.

When you order LED panels, ask to the seller for the controller chip that install, and avoid those mentioned.

I order currently all my LED panels with FM6124 controller chip, and work perfectly, also tested with ICN2038 and some more references.

Currently I have only detected incompatibility with ICN2038S and FM6126 controller chips. If you download the datasheet can you see the differences to manage the Latch signal.

SmartMatrix doesn't support FM6126A driver chips
Led module P2 128*64 1/32 driver

Thanks @pinballsp, you were indeed correct.
The good(-ish) news is that another driver supports them, although it’s slow and ESP8266 only, but hopefully its code shouldn’t be too hard to port.
I opened a new thread for that.