Hardware, firmware and software help - Prusa3D Forum

"GCode Sliced for a different printer" no matter what I do.

Lucas — Wed, 20 May 2026 21:07:49 +0000

So I have an MK3S and MMU2S printer and when I send prints to it via Prusa Slicer via the "Send to Printer" button, I always get the "GCode Sliced for a different printer".

What places are these defined and checked and how can I clear it up?

In PrusaConnect it says "Type: Original Prusa i3 MK3S/+" and perhaps that is the mismatch, but how do I change it in there to get all the settings in sync?

I know it's not the biggest deal, but it's driving me a little bonkers.

MK3S LCD dead pixels

4XS — Mon, 18 May 2026 01:01:35 +0000

Screen begin to show dead pixels after 3 years of operation. Recently it become difficult to read. Anyone had this problem and how should I fix.

MK3S Extruder Rebuild – Advice Needed on Replacement Parts and Suppliers

Fetzke — Fri, 15 May 2026 07:33:27 +0000

Dear Community,

after many years of reliable service, my MK3S extruder has started to show some issues. I’m experiencing recurring filament problems and frequent nozzle clogging. Yesterday, it eventually stopped feeding filament altogether and began clicking.

Because of this, I’ve decided to fully rebuild the extruder. I will replace all necessary components, buy new parts where it makes sense, and reprint all printable parts as well.

My hotend has clearly seen a lot of use over the years, so I would like to replace it completely, including the cables, which also seem to be in rather poor condition.

Since this rebuild will take quite some time and effort for me, I would like to take the opportunity to replace any other parts that are likely to be worn out after so many years of use.

Could anyone advise which additional components are worth replacing during such a rebuild, even if they are not yet completely failing?

I would also be very grateful for any recommendations regarding good-quality (and reasonably priced) replacement parts, as well as trusted places to buy them.

Thank you very much in advance for your help!

Flashing error

Hydrohydra — Wed, 13 May 2026 19:03:10 +0000

Hello, I get this error when trying flashing my prusa i3 mk3s. "ERROR: No valid record found in Intel Hex file"
That version number is what the printer identifies itself as in the display when the printer is on.
I am trying to flash with the file from https://help.prusa3d.com/downloads/mk3s. It is extracted and I am targeting the .HEX file. The printer is on, the cable is connected. I tried rebooting the pc and printer but no luck.
What is going wrong here?
I was a bit unsure about the version number of the printer, because I got it second hand and it was upgraded with some MMU stuff, but it was later removed, so it doesn't always match the images for identifying version, but I assumed I can rely on the printer's self report.

Here is the error report in full:

avrdude-slic3r -v -p atmega2560 -c wiring -P COM7 -b 115200 -D -U flash:w:0:C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex:i

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Nov  6 2025 at 10:47:10
                Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
                Copyright (c) 2007-2014 Joerg Wunsch


                Using Port                    : COM7
                Using Programmer              : wiring
                Overriding Baud Rate          : 115200
                AVR Part                      : ATmega2560
                Chip Erase delay              : 9000 us
                PAGEL                         : PD7
                BS2                           : PA0
                RESET disposition             : dedicated
                RETRY pulse                   : SCK
                serial program mode           : yes
                parallel program mode         : yes
                Timeout                       : 200
                StabDelay                     : 100
                CmdexeDelay                   : 25
                SyncLoops                     : 32
                ByteDelay                     : 0
                PollIndex                     : 3
                PollValue                     : 0x53
                Memory Detail                 :

                                         Block Poll               Page                       Polled
                  Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
                  ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
                  eeprom        65    10     8    0 no       4096    8      0  9000  9000 0x00 0x00
                  flash         65    10   256    0 yes    262144  256   1024  4500  4500 0x00 0x00
                  lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  efuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  calibration    0     0     0    0 no          1    0      0     0     0 0x00 0x00
                  signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00

                Programmer Type : Wiring
                Description     : Wiring
                Programmer Model: AVRISP
                Hardware Version: 15
                Firmware Version Master : 2.10
                Vtarget         : 0.0 V
                SCK period      : 0.1 us

avrdude-slic3r: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude-slic3r: Device signature = 0x1e9801 (probably m2560)
avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: reading input file "C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex"
avrdude-slic3r: ERROR: No valid record found in Intel Hex file "C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex"
avrdude-slic3r: read from file 'C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex' failed

avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: safemode: Fuses OK (E:FD, H:D0, L:FF)

avrdude-slic3r done.  Thank you.

Thermal exception problem

Šimon Diba — Fri, 08 May 2026 10:02:34 +0000

Hi, I have a Prusa MK3S and I keep getting a thermal exception warning with constant beeping. However, the temperature readings look completely normal — they rise and fall linearly as expected and stay stable during printing. The printer is able to print normally and the only issue is the nonstop alarm sound.

I suspect there may be a faulty cable or intermittent connection. Could anyone please help me diagnose what might be causing this and how to fix it?

Thermal Anomaly challenges

PJones — Wed, 29 Apr 2026 04:49:38 +0000

MK3S+ (bought second hand from print farm)
Firmware: 3.14.1
I suspect they were selling it because they were having the same problems.

I replaced the thermistor and the print fan, but the problems continue. Oddly, I can get 4 hours into a 5 hour print before it crops up for the first time. Tonight, I was about 1 hour into a 3 hour print. I've double checked that the thermistor wires are above the heater wires. Still, it beeps at about 6,000 decibels and pauses. Fortunately, I can resume it since I'm printing from an SD card.

What else can I look at to rid myself of this pain?

Printer is asking for unloading and changing filament randomly during printing

Ulf — Tue, 28 Apr 2026 13:53:10 +0000

Hi, since yesterday my MK3S+ is randomly stopping, goes to the front left and asks to press the button to unload the filament like a filament /color change was triggered, although there is nothing in the gcode. I checked the sensor readout but this seems to be normal, also rebooting the printer didn't solve the issue. Anybody an idea what could cause /trigger this behavior?

Z Calibration failing

Bryan Koszoru — Fri, 24 Apr 2026 15:51:21 +0000

hi all! Haven’t used my mk3s in about a year. I downloaded the new firmware, and it’s failing on the z calibration step with the steel sheet on:

Calibration failed! Check the axes and run again.

Everything appears to be in good condition, including belts, leadscrews, rods. PINDA sensor is activating properly. In fact, the error happens when the pinda sensor activates.

I’ve tried multiple firmwares. Same problem. Any ideas? I’m running out of options.

PINDA probe issue with mk3

Some87 — Sun, 19 Apr 2026 22:26:22 +0000

Hi I'm desperately needing some help with my mk3. This is a new printer to me I picked up used. I have experience with Prusa's as I have had a mk2s for 9 years now. I had to completely rebuild the printer as every single screw was lose on it so I never saw it running. The issue I'm running into is the first layer is super inconsistent where after I set up the live z in for a sheet then the first print has a completely different layer height then I set. I have come to the conclusion that its an issue with the PINDA probe (not super PINDA). When I was setting the PINDA height with the zip tie like the manual said the nozzle would hit the bed so I had to lower it a little lower. I'm not sure if that's causing an issue with how the probe is reading the temp but I only lowered it maybe 1 mm. Is there any way I can turn off the temp calibration setting from the PINDA?

Extrusion suddenly weird

Bent Derailleur — Fri, 10 Apr 2026 20:07:12 +0000

Hi all!

My printer has suddenly started acting weird. The extrusion does not work properly. Or how to say. Look at the pics.

First pic is supposed to be a 100x25 cube with gyroid infill.
Second pic is a gear with holes in.

PLA printed with normal settings.

There are very bad stringing, and filament does not stick.

Only thing I can think of is that it is not hot enough. Tried to increase extruder temp from 215 to 230 degree. Same problem.

Any ideas, can not think of anything. Might be something that is broken, but where to start looking? :)

Thanks