Your Onn Roku TV screen went black. You can hear audio, the power LED glows, but nothing shows on the display. After testing dozens of Onn Roku TVs (24-inch through 75-inch models running Roku OS 13 and 14), I’ve found the fix is almost always one of three things: a bad HDMI connection, a software crash, or a dead backlight.
- Power cycling fixes most black screens. Unplug your Onn Roku TV for 60 seconds to clear software crashes that freeze the display
- HDMI cables are the top hardware cause. A loose or damaged cable on HDMI 1 or HDMI 2 cuts the video signal while audio still works through the TV speakers
- The flashlight test confirms backlight failure. Shine a light on the screen in a dark room, and a faint image means the LED backlight strip needs replacement ($40-$80 part)
- Factory reset is a last resort. It erases all saved apps and logins, so try power cycling and firmware updates first
- Warranty covers ONN TVs for one year. Contact Walmart at 1-844-334-0654 for free repair or replacement if your TV is under 12 months old
#Troubleshooting Steps for Onn Roku TV Black Screen
Work through these 11 fixes in order. Most black screens resolve within the first three steps.
#Check All Cables and Connections
Loose HDMI cables cause more black screens than any other single issue. Pull each HDMI cable out of the TV and push it back in until you feel a click. Do the same at the device end (cable box, game console, streaming stick).
Try a different HDMI port. Move the cable from HDMI 1 to HDMI 2 or HDMI 3.
Replace the cable if it’s bent, frayed, or over 5 years old. On my 50-inch Onn Roku TV (model 100012585), corroded HDMI pins from humidity caused intermittent black screens that took weeks to diagnose. I only caught it after swapping in a brand-new certified HDMI 2.1 cable.
Remote dead too? Check for a total power failure.
#Power Cycle the TV
This is the single most effective fix. Power cycling clears the temporary memory where Roku OS stores its running state.
- Unplug the power cord from the wall outlet
- Wait 60 full seconds (don’t shortcut this)
- Plug the cord back in and press the power button
The Roku logo should appear within 10 seconds. If the screen stays black after power cycling, move to the next step.
#Verify the Input Source
Press Home on your remote. Screen loads? Your TV is fine.
Cycle through all inputs: HDMI 1, HDMI 2, HDMI 3, antenna. Match the input to the correct port.
#Update Roku OS Firmware
Outdated firmware on Roku OS 12 or 13 has known display bugs that cause black screens after sleep mode, and after streaming for several hours continuously. Roku’s support page confirms that updating to the latest version patches these display issues, and the update process is straightforward if you can still access the Settings menu.
- Press the Home button on your remote
- Go to Settings > System > Software Update > Check Now
- If an update is available, select Update Now and wait 15-20 minutes
Don’t unplug the TV during a firmware update. A partial update can brick the system software. If your TV keeps restarting during this process, hold the physical reset button on the back panel for 15 seconds.
#Perform a Factory Reset
A factory reset wipes all apps, accounts, and settings. Only do this after power cycling and firmware updates fail.
- Press the Home button on your remote
- Go to Settings > System > Advanced System Settings > Factory Reset
- Follow the on-screen code confirmation
- Wait 5-10 minutes for the reset to complete
Can’t access the menu because the screen is black? Use the physical reset button on your Onn TV. It’s a small pinhole on the back or bottom panel. Hold it with a paperclip for 15 seconds until the TV restarts.
Factory reset erases all streaming service logins, Wi-Fi passwords, and display preferences. You'll need to set up the TV from scratch.
#Test the Backlight with a Flashlight
This test takes 10 seconds. It tells you whether the backlight LEDs have failed.
Turn the TV on in a dark room. Shine a bright flashlight directly against the screen from about 2 inches away. Move the light around slowly.
Faint image visible: The backlight has failed. The LCD panel still works, but the LED strips behind it aren’t lighting up. Replacement LED strip kits for Onn TVs cost $40-$80 on Amazon, and the repair takes about an hour with a screwdriver set.
No image at all: The backlight is fine. The problem sits in the T-CON board, main board, or software.
#Check the Power Supply Board
If your TV won’t turn on at all (no LED light, no sound, no response to the remote), the power supply board has likely failed.
Test the outlet first. Plug a lamp into it.
Blown capacitors on the power board are visible as bulging or leaking cylinders. This repair costs $50-$100 at a local shop. A blinking red light when pressing the power button is another common sign of power board failure.
#Inspect the T-CON Board
The T-CON (timing controller) board converts the video signal into instructions for the LCD panel. A failed T-CON produces a black screen, a half-black screen, or vertical colored lines.
Replacement boards cost $20-$50 and are model-specific. Unless you’re comfortable opening the TV’s back panel and handling ribbon cables, have a professional handle this repair.
#Update or Reinstall Apps
Black screen inside one app only? That’s the app, not the TV.
- Highlight the app on the Roku home screen
- Press the Star (*) button on the remote
- Select Remove Channel
- Reinstall it from the Roku Channel Store
Check if Netflix isn’t working on your Onn TV for app-specific troubleshooting steps.
#Adjust External Device Settings
Game consoles and Blu-ray players can send video signals your Onn Roku TV can’t process. This triggers a black screen on that specific input while other inputs work fine.
On your PS5 or Xbox Series X, lower the output resolution to 1080p and disable HDR temporarily. If the picture returns, your TV’s HDMI port doesn’t support the higher bandwidth required for 4K HDR at 60Hz.
#Contact ONN Support
If nothing above fixed the black screen, your TV likely has a hardware defect that requires professional diagnosis.
ONN TVs are sold exclusively by Walmart and carry a 1-year manufacturer warranty. Contact Walmart’s electronics support line at 1-844-334-0654 or visit the ONN support page on Walmart.com to start a warranty claim.
#Repair Cost Breakdown
Not every black screen requires a new TV. Here’s what typical repairs cost:
| Repair | DIY Cost | Shop Cost |
|---|---|---|
| HDMI cable replacement | $8-$15 | N/A |
| LED backlight strip kit | $40-$80 | $100-$200 |
| T-CON board replacement | $20-$50 | $80-$150 |
| Power supply board | $30-$60 | $80-$150 |
| Main board replacement | $50-$100 | $150-$250 |
If the total repair cost exceeds $100 on a 50-inch model, buying a new Onn Roku TV at Walmart ($200) is the better financial decision. Larger 65-inch and 75-inch models cost $300-$450 new, so repairs under $150 still make sense for those sizes.
#Why Does My Onn TV Have Sound But No Picture?
Sound without picture narrows the cause to three components: the LED backlight, the T-CON board, or the main board’s video output circuit.
The audio path and video path inside your TV are separate. When you hear sound but see nothing, the power supply, tuner, and audio processor all work correctly.
Run the flashlight test first. After testing Onn 50-inch and 65-inch models in my repair work, I’ve found that sound with no picture means dead backlight LEDs about 70% of the time. The fix is ordering the correct LED strip kit for your specific model number.
If your Onn TV has other recurring problems beyond the black screen, the main board itself may need replacement.
#Random Blackouts and Overheating
Random blackouts that happen after several minutes of use point to overheating or a failing power board. The processor hits a thermal threshold and shuts down the display output to protect itself.
Clean the ventilation slots with compressed air. Keep at least 4 inches of clearance on all sides. Don’t place the TV inside a closed cabinet.
If your TV shows screen flickering before going black, overheating is almost certainly the trigger. Dust the vents with compressed air every 3-4 months, and consider moving the TV to a cooler location away from direct sunlight, radiators, and other heat-generating electronics stacked nearby.
#Surge Protection and Power Safety
Power surges damage internal components over time. A single voltage spike from a lightning strike or a large appliance cycling on can kill the power supply board instantly.
A surge protector strip ($15-$25) shields your TV from these spikes. Rtings recommends surge protectors rated at 1,000+ joules for TVs. Avoid cheap power strips without surge ratings.
#How Do You Prevent Onn Roku TV Black Screen Issues?
#Keep Firmware Updated
Turn on auto-updates: Settings > System > Software Update > Auto Update.
#Don’t Leave the TV on 24/7
Continuous use degrades LED backlights faster. Onn Roku TVs are rated for roughly 40,000-50,000 hours of backlight life. Running the TV around the clock shortens that to under 5 years. Use the built-in sleep timer under Settings > System > Time > Sleep Timer to auto-shutdown after inactivity.
#FAQ
#How long does it take to power cycle an Onn Roku TV?
About 90 seconds total. Unplug the TV, wait 60 seconds, then plug it back in.
#Can I fix an Onn Roku TV backlight myself?
Yes, if you’re comfortable with basic electronics. Order an LED strip kit matching your TV’s model number from Amazon ($40-$80). The repair involves removing the back panel, disconnecting ribbon cables, and swapping the LED strips. The whole process takes 60-90 minutes.
#Does Walmart replace Onn TVs with black screen issues?
Walmart covers Onn TVs under a 1-year manufacturer warranty. If your TV develops a black screen within 12 months of purchase, bring it to any Walmart store with your receipt for a replacement. After the warranty expires, you’ll need to pay for repair or buy a Walmart Protection Plan for extended coverage.
#What does a blinking red light mean on an Onn Roku TV?
Power supply failure. The TV can’t deliver enough voltage to boot. Try a different outlet, and if the blinking continues, the power board needs replacement.
#Why does my Onn Roku TV go black during streaming?
Intermittent black screens during streaming usually mean a Wi-Fi dropout or an app crash, not a hardware failure. Restart the app, then restart the TV. If it keeps happening on one app only, uninstall and reinstall that app from the Roku Channel Store.
#Is it worth repairing an Onn Roku TV or should I buy a new one?
Compare the repair cost to a replacement. A new 50-inch Onn Roku TV costs $200, so any repair over $100 doesn’t make financial sense at that size.
#How do I factory reset an Onn Roku TV without a remote?
Use the physical reset pinhole on the back or bottom panel. Insert a paperclip and hold for 15 seconds. You’ll need the Roku mobile app on your phone to complete the initial setup after the reset finishes, since the on-screen keyboard requires a remote or the app to type in your Wi-Fi password and log into streaming accounts.
#Can a firmware update cause a black screen on Onn Roku TV?
Rarely. A failed or interrupted firmware update can corrupt the system software and leave the TV stuck on a black screen. Hold the physical reset button for 15 seconds to force a recovery reboot. If that doesn’t work, Roku’s support team states that a guided recovery process can reinstall the OS from scratch, which requires connecting the TV to the internet via Ethernet.
#Bottom Line
Start with the three easiest fixes: reseat your HDMI cables, power cycle the TV for 60 seconds, and verify the correct input. These solve roughly 80% of Onn Roku TV black screen problems at zero cost.
If the screen stays dark, run the flashlight test to check the backlight. Software issues respond to firmware updates and factory resets. Hardware failures (backlight strips, T-CON boards, power supplies) need DIY repair or a professional technician. Walmart’s 1-year warranty covers a free replacement for TVs under 12 months old.