Printer does not boot, only black screen
Hi fellas!
After I finished the assembly of my Core One and tried to start it for the first time, the only thing that happened was the ventilators on the nextruder started and the screen showed black. It wasn´t dead, just all black.
After about 10 seconds a beeping signal started and I turned it off. Tried that three times.
Electronics on this scale is new to me (only built PCs and stuff like that) and I´suspect I maybe have broken something in assembly. Is there anywhere you can point me to by that description?
Couldn´t find anything about that error anywhere.
For any new build/new machine problems the first place to look for help is Prusa Support via the chat option.
You will need the machine's serial number and your account details.
Cheerio,
RE:
Second that. CONTACT PRUSA BY THE "CHAT NOW" BUTTON !
(It is typically in the lower right of the web site. But you might have to navigate to the correct website - such as the build web site)
RE: Printer does not boot, only black screen
Chat GPT claims.... (CAUTION: ChatGPT is often completely WRONG, but never in doubt)
1: LCD Ribbon Cable Connection not being fully seated is the #1 cause.
2: Power Delivery Cables may not be correctly seated, or ground wire may be loose.
3: An issue with the Nextruder Cable
4: Reseat the toolhead and bed sensors
=================
✅ 1. Check the LCD Ribbon Cable Connections
This is the #1 cause of a black screen at first boot.
Please verify:
The LCD ribbon cable is fully seated on both ends.
The connector on the Buddy board should be fully inserted — you should not see any pins.
The cable must not be twisted or offset by a row of pins.
Common mistake: One end shifted left/right by one pin row → black screen + beeping.
✅ 2. Ensure the Power Delivery Cables Are Correctly Seated
Double-check the following on the Buddy board:
Both 24V PSU leads are fully tightened and seated.
The ground wire is secured.
No wire strands are loose or touching adjacent terminals.
Even if fans turn on, a loose ground can cause beeping and no boot.
✅ 3. Inspect the Nextruder Cable (the big umbilical)
If this cable is not fully seated:
Fans spin (powered separately)
MCU fails to initialize → black screen
Board may emit beeping after watchdog timeout
Please:
Remove the toolhead cable at the toolhead and at the electronics box
Re-insert until firmly latched
✅ 4. Reseat the Toolhead and Bed Sensors
Miswired or partly connected sensors can halt boot on the Core One:
Nextruder board 8-pin micro-fit connectors
Tramming probe connector
Thermistor and heater cable seating
A half-clicked connector can cause the board to fail boot checks.
✅ 5. Check for an SD Card Problem
On rare cases, a corrupt firmware card will cause a black screen + beep.
Power off the printer
Remove the microSD card from the Buddy board
Reinsert it fully and reboot
If it continues, we can guide you through reflashing.
🔧 If nothing above resolves it
The beeping after ~10 sec is the Buddy board’s watchdog error, meaning the MCU is alive but failing early self-tests.
At that point, we’d recommend:
Sending us a clear photo of the Buddy board wiring
Photo of LCD ribbon connection
Photo of the toolhead cable connections on both ends
We can usually diagnose within a minute from the photos.
If you'd like, feel free to describe what the beep sounds like (single repeating, rapid bursts, etc.) and I can narrow it further.
RE: Printer does not boot, only black screen
Ah, yes. Now I found it Also I think my browser was blocking it, but I now I can open it.
Anyway, thanks, guys.
RE: Printer does not boot, only black screen
Chat GPT claims.... (CAUTION: ChatGPT is often completely WRONG, but never in doubt)
laughing out loud (OT).
In the past, the answers I got were often brilliant, probably thanks to the power consumption of a small country, courtesy of the marketing budget. It used to elaborate on and apologize for its mistakes.
Nowadays it's even telling me "I am confused" when reality (as an impartial software stack) rejects its truths that flip sign between one reply and the next ...
RE: Printer does not boot, only black screen
It depends upon the personality that they have endowed it with.
The default one seems to be very obsequious ('that is a brilliant question', 'oh, of course you are right', 'etc')
Issues:
1: Apparently some/most models are not very good at math at the present time. That may because they are math models and not calculation machines. So they gave a wrong answer to a financial problem but insisted they were correct.
2: I asked one for a list of all Presidents... It ended the list at Biden... When called on that it insisted Biden was the current president. I tracked that error down to the 'training date' for the model. It was last trained when Biden was President. (a, Trump, President Trump who?)
3: I was trying to get the model to give me a particular joke from a TV show. It was having trouble with that. It certainly could not explain the joke. Then I had some fun teasing it by claiming something completely different and absurd was the correct answer. We moved it down that rabbit hole three times before I got tired of playing. But it always agreed my absurd answer was correct.
4: All of its answers are from written information somewhere. It is just faster at finding it than we are. But if it pulls up garbage answers, then that is what we get. Such as for FamilyTreeDNA web site, the ChatGPT was INSISTING that there were menu options available to group the DNA results. Eventually I confirmed with tech support that the AI was hallucinating. There was no such menu item.
So yeah, while sometimes its answers are brilliant, sometimes they are absurd. Such as when the AI kept making illegal moves in a game against Gotham chess.
RE: Printer does not boot, only black screen
The staff are VERY HELPFUL and VERY KNOWLEDGABLE about their equipment. They helped me out many times (at least five, perhaps more) during my build and initial startup difficulties !
RE: Printer does not boot, only black screen
what’s the wait time today?
RE: Printer does not boot, only black screen
Chat GPT claims.... (CAUTION: ChatGPT is often completely WRONG, but never in doubt)
I think it is safe to assume that everyone here knows about ChatGPT and has figured out how to ask it, if so inclined. (After all, we have built a 3D printer following online instructions, and managed to register and post on this forum.😉) Hence, pasting ChatGPT advice into a post without adding any perspective of your own beyond a generic "this might be wrong", does not add much value.
If ChatGPT gave you a particularly brilliant piece of advice, I would love to read about it. But in a post that includes your own perspective: Why do you think it is brilliant? How did you confirm that it was correct?
Oh, and I would appreciate if you could fix the formatting before re-posting ChatGPT quotes. They are wordy to begin with, and the extra-large line spacing and lack of bullet points makes them really hard to read in my view. Thanks!
RE: Printer does not boot, only black screen
As it seems the robot was right in this case. It was the LCD ribbon cable. It wasn´t plugged in properly.
Running set up and diagnostics. Looking good.
Thanks again, fellas!