PCMS-3812 Pixel Error Troubleshooting

Synopsis: If your touch screen shows an error code that says Error: Pixel, it indicates an issue with one of the display cards located inside the sign case. This error can prevent you from activating a message on your sign.

Please note this procedure applies to both trailer-mounted, and truck-mounted 3812 units. 

• Level: Easy
• Time required: Will vary depending on experience but should take roughly 5-10 minutes.
• Additional equipment required: Philips screwdriver, spare display card, spare data cables

3812 Sign Case Overview

• Matrix size X and Y: 48 x 27
• Cards X and Y: 6 columns of 3 display cards per column
• Total cards: 18

Figure 1 - Sign case wiring

1. Log in to the V-touch controller and press Toggle, then Options, then Pixel Test

Figure 2 - How to get to pixel test

2. Press Start on the pixel test screen to see where the pixel issue is

Figure 3 - Pixel test screen

3. To further isolate the issue, go to the communication card inside the sign case and swap lines 1 & 2

Note: The cables you move on the communication card above will vary depending on where the error is. For example, if your error is in line 3, you will swap lines 2 and 3 instead of 1 and 2.

Figure 4 - Lines to swap on the communication card

4. After swapping the cables, go back to the Pixel Test screen and press Start once. After a few seconds, press Start again. The error should have moved to line 2

4.1. If the error moves to line 2, continue to the next step

4.2. If the error does not move, it could be an issue with the communication card

Figure 5 - Error moving

Note: With the error moving to column 2, it confirms the original error in column 1 because the error followed when we moved the wires

5. Place wires 1 & 2 back into their respective ports on the communication card, the error will then return to line 1

6. Press Chessboard on the Pixel Test screen and go to the front of the sign

How the Chessboard Pixel Test works:

Figure 6 - Data flow during chessboard pixel test

6.1. Starts on the top left display card of Column 1

6.2. Data will go through each display card in the column and light up the LEDs on them 

6.3. When it gets to the end of the column, the end line jumper will send data back to the communication card and keep going into Column 2

6.4. If there is an error in Column 1, the data will not be able to flow to Columns 2, 3, 4, 5, or 6, so the cards will not light up

 6.5. It is very important that the end-line jumpers are plugged in at the top of each column

How to identify the bad display card in Column 1:         

6.6. The data will light up the display cards one by one in Column 1

When the pixel test stops running, it means it hit a defective display card

Figure 7 - Pixel test stopping on defective display card

In Figure 7, display card #3 in Column 1 could be defective as it does not light up after receiving data

7. Solutions to fix pixel error

7.1. Replace the bad display card with a known working display card and your Pixel Error will go away. If you do not have any spares, you will need to purchase some

7.2. You can also try swapping cards 3 and 6, go back to the pixel test screen, and check if the pixel error moved back to Column 2. If it does, it means the display card you just moved from 3 to 6 is defective because the error followed it

7.3. It is normal that display cards 4 to 18 do not light up, as the data is not making it due to the bad display card

If you require any additional help, contact our toll-free number at 1-888-488-7446 or email us at [e-mail]