Maker Pro
Maker Pro

Help Repurposing an LED Sign Panel

TheGalantOne

Apr 16, 2024
3
Joined
Apr 16, 2024
Messages
3
Hello Everyone,

My friend owns a store and his big LED sign went bad. Probably the main board. Well we took it apart and found the display was assembled in separate panels. I have a couple of these panels and was getting ready to strip them down for parts. Then I realized to use the LED Matrixes with an Arduino I was just going to have to recreate a board very similar to the one they were already on. So now I am trying to figure out how to use the panel as is.

I can only see the traces on one side of the board since the other side is covered in LED Matrixes. If that wasn't bad enough it is a multilayered board so I really only get a small view of the circuit. The board seems split in two halves each with a 14 pin input and 14 pin output, wich allows you to chain them together. I would love to figure out what these 14 pins do. I was hoping some one could look at the material list below and give me an idea. For example the CMOS Octal Bus Buffer. Are they using a standard bus architecture I can read more about?

Hope someone can help.


(2) 14 pin inputs, (2) 14 Pin outputs, Black 12AWG Ground wire, Red 12AWG , Orange 12AWG VDD Power


QtyParts On Board (Chip number then Data Sheets found)
208x8 Bi-color Led matrix
20A6277x 8-Bit Serial Input Constant Current Latched LED Driver.
274HC240D CMOS Octal Bus Buffer
242Z4XRJ-HC14 possibly an SNx4HC14 Hex Inverter
16IR44SH-4L2N-F7304 possibly an IRF7304 HEXFET
2MAX7000 EPM7032
414 pin connectors
?Lots of little resistors on the LED driver chips

 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,767
Joined
Nov 17, 2011
Messages
13,767
Without circuit diagram - nearly impossible.
You may have to sacrifice one panel, remove the LEDs and trace the connections on both sides (hopefully and likely the board is double-sided only) to create a schematic from the pcb. Here's one guide how to do this. Other methods are possible, too.
 

TheGalantOne

Apr 16, 2024
3
Joined
Apr 16, 2024
Messages
3
Here are some photos. You can't read the text but if can give a better vision of the big picture.

Thank you for any advise you can offer. I know I could just buy a more modern and easy to work with panel. This is more of a challenge project that I am hoping to learn from.
 

Attachments

  • thumbnail_image0.jpg
    thumbnail_image0.jpg
    476.9 KB · Views: 4
  • thumbnail_image1.jpg
    thumbnail_image1.jpg
    330 KB · Views: 4
  • thumbnail_image2.jpg
    thumbnail_image2.jpg
    566.2 KB · Views: 4
  • thumbnail_image3.jpg
    thumbnail_image3.jpg
    629.5 KB · Views: 4

TheGalantOne

Apr 16, 2024
3
Joined
Apr 16, 2024
Messages
3
Without circuit diagram - nearly impossible.
You may have to sacrifice one panel, remove the LEDs and trace the connections on both sides (hopefully and likely the board is double-sided only) to create a schematic from the pcb. Here's one guide how to do this. Other methods are possible, too.
That is such a good guide. There is so much there, I just quickly reviewed it and learned a ton. I'll do a full read over the next few days. My hope is I can apply power to the board and just start passing square waves to some of the pins on the bus until a light comes on. I uploaded some pics in another post. Maybe there is enough information there so save me from desoldering. If a can't getting working that way I will follow that guide, after all I am doing this as a learning exercise and will probably learn the most from truly tracing it out.
 
Top