Problem with MAX 7219 LED display

Other Hardware Displays
1

Hi,

I purchased three MAX 7219 LED micro controller 4 in 1 displays from Paialu, linked them together into a single display, wrote some code and got the display to work well with my Arduino uno. (I am using the Majic Designs libraries for the MD_Parola.h and the MD_MAX72xx.h)

Recently I purchased three more of the same LEDs from the same supplier. For some reason I cannot get these new LEDS to display correctly when using the same Arduino code that works with the initially purchase display. I communicated with the supplier and was told they are not aware of any wiring changes in the displays. But something is different.

Here is what I see when I use the new (3 - 8x8 LEDs linked together) display. Let's say, for example, I have a message where all zero's should be displayed across the display. In some cases I see the complete zero displayed. In other cases, as we move across the display, I see the left 3/4ths of the zero in one 8X8 square and what appears to be the remaining right 1/4 of the zero two 8x8 LEDs over.

Does anyone have an idea what the problem may be here?

Thanks in advance for your assistance.

Scott

2

Given that you swapped nothing but the display, I think we want the actual link to the displays (I presume they are the standard "FC-16") and some photos in adequate lighting.

3

Have you run the MD_MAX72xx_HW_Mapper example program for each batch of displays? You may very well find out that they are not actually the same.

Don

4

Hi Paul__B,
Thanks for the reply.
I am sorry but I do not know what you mean by wanting the actual link to the display (FC-16). Please advise.
Thank you.

floresta,
Thank you for the reply. I was not familiar with the MD_MAX72xx_HW_Mapper but I will look for this example and run it.

5

Post a link to the actual display that you have bought e.g. Ebay sale.

Compare the photos on the website especially the pcb. Verify the accuracy. Describe any differences.

This advice applies to any hardware question. It will identifiy new variants appearing on the market.
A picture is worth a thousand words.

David.