LCD Screen Not Working After Replacing the Fuse in Your Printer?

Question: 
I put a new fuse in my printer, and it looks like it works, but the LCD screen doesn’t work. There’s no light on the LCD screen. The on/off button is still lit, and I believe all the flex cables are correctly connected. Can you tell me what might be going on?
 
Answer:
Thanks for contacting BCH Technologies regarding your printer issue. I apologize for the delay in responding, and I understand that printer issues can be urgent. I appreciate your engagement and continued support, especially with our BCH Technologies YouTube channel. Your feedback is invaluable in helping us refine our technical expertise, and I’m happy to assist you with troubleshooting.
 
So, let's get into the problem with the printer's LCD screen. Since you’ve replaced the fuse, and the printer appears to be working, the problem is probably in the LCD itself or its connections. Here’s a rundown of the most common reasons and what to do about them.
 
Why the LCD Screen Issue Could Be Happening:
 
LCD Backlight Failure:

• Backlight failure is the most typical cause of an LCD screen being blank after replacing a fuse. The screen itself may be fine, but if the backlight is out, it will look like the screen is blank. You can check this by shining a flashlight on the screen at an angle. If you can see faint images or text, your backlight is most likely the culprit. If that holds, you must replace the backlight or the LCD panel.

Faulty Flex Cable Connection:

• Even if you are confident that all the flex cables are correctly connected, there could still be a loose or misaligned connection. Flex cables are flimsy and can be displaced quickly during repair or handling. Please make sure all cable connections are firmly seated, specifically where the LCD connects to the mainboard. The little connectors are particularly finicky, and there is no margin for error — it was finding that out by trial and error.

Damaged LCD or Components:

• If you damage the LCD screen or any of its associated components (such as the driver circuit) while replacing the fuse, it could also lead to screen failure. If they handled that area while replacing the fuse, they might have caused damage while they were in there. In these cases, the LCD screen or supporting components must be replaced.

Power Supply to the LCD:

• It remains blank when the LCD does not receive the power. There is a good chance the fuse you replaced is not the only device delivering power to the screen. Next, check if the LCD is being powered. Check the power lines to verify they are intact and supply a proper voltage to the display.

Steps to Troubleshoot:
 
Recheck connections of flex cable:
Try this first: unplug and reseat all the flex cables. Check for bent or misaligned pins, as a single bent pin can result in a malfunctioning LCD. Ensure the wires are correctly connected, particularly those connecting the LCD to the mainboard.
 
Inspect the LCD Backlight:
Direct a flashlight at the LCD screen at an angle. If you perceive faint images or text, the problem is likely in the backlight. In this case, you'll likely have to change the LCD panel or the backlight.
 
Examine the Power Supply:
If you have a multimeter, test for power at the connection point to the LCD. Compare the voltage readings to the expected values, which should be specified in the printer's service manual (if one exists). If the power supply voltage is low or even absent, there is an issue with the PSU.
 
Look for More Blown Fuses:
If you replaced the primary fuse, secondary fuses on the board may be affecting the LCD power. Visually inspect that board and see if there are any other blown fuses.
 
Additional Tips:
If you are still experiencing problems and there may be a problem with your machine, consider using specific service diagrams or repair tutorials for your printer model. You can also visit our YouTube channel for detailed repair videos that shed some light on this problem.
 
Various ambiguous aspects are available in the process of fixing printers due to the hands-on prospects of the issues. I'm sorry, but unfortunately, we do not offer printer repair support, troubleshooting, or suggestions remotely. We provide an onsite diagnostic and fixing solution at our regional Printer Repair Service facility. Because of demand, we are working on a first-come, first-served basis, and it may take several weeks for us to check your printer for repair. We provide services to fix the whole printer or the individual parts with proper direction on all procedures. But ours are not necessarily the cheapest. So we encourage you to get help by searching for yourself. One of the best places to start is to head to our YouTube channel, where you'll find many troubleshooting videos. On YouTube’s homepage, the search icon is your best friend for locating tutorials suited to your printer.
 
Once again, thank you for sticking with us to this point. We trust that these measures will help you address your printer's LCD screen issue.