Was getting issues with Z getting too close to the nozzle so wanted to restart the printer.
After restart, LCD was showing blocky display broken images with firmware prompt.
I never do firmware update so i dont brick the device.
I cycled the power one more time and now LCD is just black.
No back light, nothing.
Printer is still working. Connected to internet etc.
Able to use bambustudio but LCD is blank
Cannot turn lights on using bambustudio.
Something is dead and i dont know what.
I do have LED strip connected to the board that i bought on amazon. Maybe thats what causing power issues to the LCD ?
The BIGTREETECH lcd does work
Given that the AP board connection is only good for 300mA and the light on amazon need at least 1A, I wouldn’t be surprised you killed your AP board if this light is the type that connects to the small connector rather than the USB, many did…
I’ll second the damaged AP.
Like Jon said, remove the lights and Panda Touch. Reboot and see what happens.
If you’re running the Touch through the USB and it’s not working, I’d make plans to replace the board. Be sure to get the right board.
i only had LED strip>
Disconnected that, no change.
No voltage on the breakout board.
Resistance is mega ohms on both board and LED strip.
Where is the origin of the voltage on that breakout board ?
I guess what i am asking is: since the beakaway board is part of the LED strip mod, where does the voltage come from that powers the LCD ?
The BIGTREETECH lcd is powered just fine and i dont really understand why that works but original LCD does not. Are they not on the same power rail ?
A dark or blank LCD can have several causes, but in this case the symptom progression matters. Seeing blocky or corrupted graphics before the screen went fully black suggests a problem in the LCD subsystem itself (controller, power, signal integrity, or cabling), not just a simple backlight failure.
That said, one quick diagnostic is the flashlight test. In a darkened room, shine a bright flashlight at an angle against the screen. If you can faintly see menu elements or text, the LCD panel logic is still working and the failure is likely limited to the backlight circuit or its wiring. If nothing is visible at all, that points more toward a failed LCD controller, power rail, or cable.
Since the printer is still reachable and usable from Bambu Studio, the main control electronics are clearly alive. That already indicates the AP board is functioning at a system level, so a completely “fried” board is unlikely.
One important clarification: the BIGTREETECH Panda Touch display does not validate the printer’s internal LCD hardware. It connects to the printer over Wi-Fi (MQTT/network control) and is completely independent of the printer’s built-in LCD, ribbon cable, and backlight circuits. Its ability to work only proves that the printer boots and communicates on the network.
Additional checks worth doing:
Power the printer down and re-seat all LCD-related cables, especially the ribbon cable connecting to the LCD. Inspect for bent pins, partial insertion, or visible damage. Taken from the Wiki:
Disconnect any aftermarket hardware, including the added LED strip, and retest. Aftermarket loads can overdraw or disturb low-voltage rails and can plausibly contribute to LCD or backlight damage.
If the front-panel buttons are unresponsive as well, that further supports a local LCD or LCD-power issue rather than a core control-board failure.
Taken together, these symptoms most strongly point to a failure in the original LCD assembly or its power/backlight circuitry, not firmware and not the main control board.
Or you can simply swap out the LCD panel and use that as your first troubleshooting step.
The wiki on this is pretty good, especially the YouTube video.
The screen is controlled directly by the main processor. There isn’t a separate processor controlling the screen like the X, H and P2S printers.
You have also stated that you’ve “never done a firmware update” so there should be no reason for it to be a “firmware issue”.
My guess is that either with is an issue with the harness connection or there was too large of current draw and backlight or backligh driver didn’t like it.
i think i just wasted 40 bucks on a new LCD.
there is no power with or without the LCD that would go to LEDs strip.
0v whats so ever.
Does that mean LCD is dead and does not generate voltage for the LED strip or what ?
I am not sure the source for LED lights to get their voltage from.
Its connected to the board directly behind the LCD so i would image that board is dead or what else ?
It is not glued. The LCD is friction-fit and intentionally tight so it does not work loose due to printer vibration. It is designed to be hard to slide out. Use firm, steady pressure and slide it straight out - do not pry or twist it. Be careful not to snap it. Once it starts to move, you can pull it forward to fully disengage it.
I understand why you might suspect firmware, but based on the failure mode you described, this does not indicate an LCD firmware issue. If it were firmware-related, the printer would typically fail more broadly rather than showing a localized LCD symptom.
If you want to prove this to yourself, you can follow the official Wiki instructions to downgrade the firmware and then flash back to the latest version. That will let you verify behavior across versions using a supported method:
Not to be “that guy”, but the AP board controls the LCD screen. Usually if the screen is dead it’s the AP board is dead. There IS one cable that runs from the MC to the LCD that, if cut, will cause the LCD to flip out. I may have misunderstood and you were thinking about it. If so sorry.
I have too much experience with the AP Board. Too much.
