Why are parts of my sign not lighting up or showing dead pixels?

Several factors can cause parts of your LED sign to not light up or display dead pixels, resulting in black spots or distorted images. Below are the common causes and steps to troubleshoot them for customers, with additional technical guidance for support staff.

Customer Troubleshooting Steps:

1. Dead Pixel or Module Failure
   • What it looks like: Individual LED bulbs or small groups on a module are out, causing black spots or a specific color (e.g., red, blue) to stay on constantly, distorting the image.
   • What to do:
     • Check if only a few bulbs or a small area of the module is affected.
     • If confirmed, the module likely needs replacement.
     • Visit our self-help desk at Repair Request Form and submit a form to request a replacement module.
     • Specify your sign’s pixel resolution (e.g., P10, P8, P6) and the IC type. If you don’t know the IC, follow the instructions at [insert IC identification link] to locate it.
     • If using Viplex or VNNOX, use Nova LCT software to read the IC information from your sign. Find instructions at [insert Nova LCT link].
     • Once you receive the replacement module, power off the sign, swap the affected module with the new one, and return the faulty module for repair using the provided shipping label.
2. IC Failure
   • What it looks like: A cluster of bulbs (often in blocks of 8 or more) is out, or an entire line on the module is discolored (e.g., stays pink or blue).
   • What to do:
     • Identify if a block or line of bulbs is affected, indicating an IC failure.
     • The solution is the same as for dead pixels: request a replacement module via the self-help desk at [insert support link], providing pixel resolution and IC details.
     • Follow the same replacement and return process as above.
3. Power Supply Outage
   • What it looks like: A group of modules (up to 12 for pre-2019 signs, or 2-3 for post-2019 signs) is out, often in sequence or rows.
   • What to do:
     • For post-2019 signs, if 2-3 sequential modules are out, it’s likely a power supply issue. For pre-2019 signs, check if up to 12 modules are affected.
     • Power off the sign and open the sign (pre-2019) or remove affected modules (post-2019) using an Allen wrench.
     • Locate the power supply and check if the green power light is on. If not, the power supply needs replacement.
     • Visit our parts locator at [insert parts locator link] to identify the power supply for your sign model.
     • Request a replacement power supply via the self-help desk. For pre-2019 signs, we recommend hiring an electrician to verify input voltage (120V or 240V) and perform the replacement.
     • Install the new power supply and test the sign.
4. Video Card Issues
   • What it looks like: A large portion of the sign is out (e.g., 9 modules for a 3x6 sign, 16 for a 4x8 sign, or 9 for a 3x9 sign per video card).
   • What to do:
     • Check your sign’s wiring diagram at [insert wiring diagram link] to confirm the number of video cards and modules per card.
     • Power off the sign and access the back or remove the module in front of the video card.
     • Ensure signal cables are secure (listen for a click when reconnecting).
     • If the issue persists, use the troubleshooting kit’s Ethernet cable to bypass ports by connecting directly between video cards.
     • If the screen lights up, order a replacement cable kit with ports and connectors at [insert support link].
     • If there’s no light on the video card, check the adjacent power supply for 5V DC output. If the power supply is functional, request a replacement video card.
     • For XM Player-controlled signs, order a preprogrammed card. For Viplex or VNNOX, order a standard card and use Nova LCT to apply the configuration file (instructions at [insert Nova LCT link]).

Support Staff Technical Guidance:

1. Dead Pixel or Module Failure
   • If equipped, verify module failure by running Nova LCT diagnostics to confirm dead pixels. Check module model (e.g., P10, P8) and IC type using the sign’s configuration file.
   • Ensure replacement modules match specifications. Provide customers with a return shipping label and track the faulty module’s repair status.
   • Escalate to a technician if multiple modules fail simultaneously, indicating a potential controller issue.
2. IC Failure
   • Confirm IC failure if a block of 8+ bulbs or a line is out. Use diagnostic software to isolate the issue to the module’s IC.
   • Follow the same replacement process as for dead pixels. Inspect returned modules for IC defects and document patterns for quality control.
3. Power Supply Outage
   • For pre-2019 signs, confirm power supply capacity (up to 12 modules) and test output voltage (5V DC) with a multimeter. For post-2019 signs, verify 2-3 modules per power supply.
   • If the green light is off or voltage is absent, replace the power supply. Ensure input voltage (120V or 240V) matches the sign’s requirements.
   • Guide customers to use the parts locator for model-specific power supplies. For complex replacements, recommend electrician assistance and provide a referral list if needed.
   • Log power supply failures to track reliability trends.
4. Video Card Issues
   • Confirm the number of affected modules matches the video card’s capacity (e.g., 16 for 4x8 signs). Check wiring diagrams to verify card layout.
   • Test signal cables for continuity and inspect ports for damage. If bypassing ports resolves the issue, ship a replacement cable kit.
   • If the video card lacks power, test the adjacent power supply. Replace the video card if power is present but no light is detected.
   • For XM Player signs, ensure preprogrammed cards are shipped. For Viplex/VNNOX, provide Nova LCT configuration files and remote setup support.
   • If the entire sign is off, verify software communication (Viplex/VNNOX). Resend configuration files, check input settings (internal/HDMI), and test controller connections. Replace the control card if no activity is detected after testing.

If troubleshooting doesn’t resolve the issue, submit a support ticket at Submit a ticket | LED Sign City with your order number and a description of the problem for further assistance.