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Chapter 15 — Troubleshooting index

Every failure this manual already knows about, filed by symptom instead of by chapter. Nothing here is new advice: each row points at the step, checkpoint, warning callout or Common mistakes bullet that owns the fix, in Chapters 00–14 and the print chapters. Use it at the bench when what you have is "the X carriage binds near one end" rather than "Chapter 05".

Revali shrugging at a failed gate
Something is wrong and a step here already expected it. Start at the symptom. Panic scales poorly.

Time: none — this is a reference page, not a build chapter.

Prerequisites: none. Readable at any point in the build.

Tools: whatever the step you land on calls for. The multimeter rows all assume the machine is unplugged — see Ch 00a Step 00a.4.

Printed parts: none. Hardware: none.

Read first

  • Find the symptom, then go to the step. Do not fix it from this page. The rows are compressed to fit a table; the step has the orientation, the picture and the exact numbers.
  • This index does not invent fixes. If your symptom is not here, it is not a symptom this manual has an answer for — go to Not covered here and ask, with the four pieces of information listed there.
  • Anything smelling, smoking or tripping a breaker is not a troubleshooting problem. Cut power at the wall and go to Ch 00a Step 00a.12.
  • Ch 13's own What if table is the primary source for first-start faults and is more detailed than the rows here. This page indexes it; it does not replace it.
  • Order matters more than any single fix: PID → soak → probe accuracy → QGL → square → Z=0 → mesh. A symptom that appears out of that order is usually the order, not the part (Ch 13 Common mistakes).

Start here — tap through to the step

Four taps, worst case: the phase you are in, the symptom, what you actually see, then the step that owns the fix. Everything below is drawn from the symptom tables further down this page — the same fixes, the same links, one question at a time. If the tree runs out before your symptom does, use the tables.

  • Printing a plate on the Core One+

    • The cube misses Gate A

      • X and Y read 0.10 to 0.30 mm over

        Shrinkage compensation or XY compensation is not zero, or flow is high. Confirm 0 % and 0, then bring the extrusion multiplier down in 1 % steps. Never negative XY compensation. Gate A · B00.5

      • Z is off, or the first layer is wider than mid height

        Squish or elephant-foot compensation. For Z, fix the sheet, the glue film or the nozzle seat rather than saving a nudge, because the Core One+ keeps none. For the first layer, elephant foot in 0.05 mm steps. B00.4 · Gate A

      • A corner peels along one layer line at the snap test

        The chamber is too cold or the part fan is too high. Drop min/max fan to 0 / 15 % and keep the 40 °C chamber gate. Gate A

    • A bore or a boss fails Gate B

      • A 625-2RS or F695 seat is tight or loose

        Flow, or shrinkage compensation that is not zero — the seats are drawn for 100 %. Tight means extrusion multiplier down 1 % and reprint; loose means confirm 0 % shrinkage. Never enlarge a bore with compensation. Gate B · B01.7 · B03.4

      • A heat-set boss bulges, or the insert sits crooked

        The iron is too hot or pushed too fast. This is technique, not the slicer: practise on the coupon until two in a row come out flush. Gate B · 00.13

    • Something went wrong on the bed

      • A long flat part lifted at the ends partway through

        Missing or old glue film, a chamber that started cold, or a reprint without its brim. Sheet per the print-sheet section, hold the chamber gate, and put the brim on that object only. Print sheet · Orientation & brim

      • The first layer is glassy and featureless, or gappy and ridged

        The loadcell zeroed Z on a sheet that is not seated, a lumpy glue film, or a nozzle not fully seated. Fix the cause: a Live Adjust Z nudge is per print and is not saved. B00.4 · calibration item 3

      • A brim appeared on flat grills or clips that should have none

        The global brim was set by hand. Clear Print Settings, Skirt and brim; brims live per object inside the committed projects. Orientation & brim · B02.4

    • The slicer or the spool

      • The preset reads bare, or B00-P1 estimates far from 3 h 58 m

        The project's configuration did not load: the wizard was not run, or the 0.4 HF nozzle variant is not installed. Run the Configuration Wizard with HF ticked, then reopen the project. B00.0 · one-time setup

      • The spool ran out mid-plate

        One runout is predicted, on a plate with no bearing seat. Let the runout sensor pause, load the next spool and resume; never plan one on a bearing-seat plate. Spool ledger

    • The printer stopped mid-plate

      • It paused and asks for filament

        The runout sensor paused it. Load the next spool and resume from the printer screen. When the printer stops · Spool ledger

      • The power went out

        If the printer offers to resume when power returns, accept only if the part is still firmly stuck to the sheet. Otherwise clear the sheet and reprint the plate. When the printer stops

      • A "bed not aligned" or Z-alignment prompt

        Cancel the print, run the printer's Z alignment, and start the plate again. If it comes back, brush the hot nozzle tip clean and check nothing is under the sheet. When the printer stops

      • It taps the same probe point again and again

        Ooze on the nozzle tip or heater noise on the loadcell. Cancel, brush the hot tip clean, and start the plate again. If it loops again, stop the run and read the section linked here. When the printer stops

      • Spaghetti: a part came loose

        Stop the print and let everything cool before you touch it, then clear the sheet. Fix the glue film, the brim or the chamber start, and reprint the whole plate. When the printer stops · Print sheet

  • Frame and motion, with nothing powered

    • A carriage or the toolhead binds

      • A tight spot near one end of X travel

        A rail is not centred on its extrusion. Re-centre it and re-tighten from the middle outward. 05.44 · 05.33

      • Stiffness that grows steadily toward one end

        The gantry is racked. Square it in Ch 06b, and do not loosen rails to make it feel better. 05.44 · 06b.14

      • A Z carriage is tight the whole length

        The rail screws were tightened from one end, bowing the rail. Back them off and re-tighten centre outward. 02.07

      • A carriage is notchy or gritty and getting worse

        The rail went on dry, or grease was left on the rail surface. Flip and pack needs the back of the rail. 00.19 · 00.18

    • A belt is noisy, rubbing, or will not tension

      • A belt runs clean at one end of travel and rubs at the other

        A half twist somewhere in a long run. Sight down each straight run; the teeth must face the same way at both ends. 07.29

      • A belt shreds against a flange

        A bearing pair is fitted flange to flange or flange in. Open the stack: the plain faces must meet. 04.07

      • The A and B belts rub against each other

        The pulleys are at the same height, or the B pulley is hub down. A is 16.5 mm hub down, B is 6.5 mm hub up, both re-checked with the jig. 04.24 · 04.33

      • A and B tension will not converge

        Unequal belt lengths, unequal tail protrusion, or a belt rubbing. Cut both together, equalise the tails, inspect every idler. 07.33 · 07.08

      • The frequency reads far too high and will not come down

        You are reading a harmonic, not the fundamental. Take the lowest peak, three plucks, in a quiet room, over a measured 150 mm span. 07.31 · 07.30

      • Belt noise that tension changes do not fix

        Crushed idler pockets from over-tightened 20T idler bolts. Those bolts only locate the idler and they thread into plastic. Ch 05 Common mistakes

    • The bed, or a part that will not sit right

      • The plate tacos on the first heat to 110 °C

        All four bed bolts were tightened; the plate has to float on three. One bolt only, because the plate is meant to expand. 03.17

      • A bed bolt strips its T-nut on the first tighten

        The manual's M3×16 barely engages through a 10 mm plate plus spacer. Use the M3×20. Ch 03 Common mistakes

      • A drive-frame post strips and will not hold

        An M5×30 BHCS was torqued into plastic. Stop at closed and snug; a stripped post means a reprint. Ch 04 Common mistakes

      • A skirt or COB mount is bowed and will not sit flat

        A warped print, caught after assembly instead of at the flat-reference check. Check parts against the flat reference as they come off the plate. print/B07 · print/B08

    • The panels and the door

      • A side panel is scored by the gantry

        1 mm foam tape was used on the sides. 1 mm goes on back and top, 3 mm on the sides, where it works as a standoff. 11.56

      • The Clicky-Clack door racks, or the latch will not catch

        A loose M5×45 dowel fit, or the door is hung wrong at the hinges. Re-hang at the hinges: the latch is almost never the problem. 11.62

  • Electronics and startup

    • Nothing powers on, or something was destroyed

      • Nothing powers on at all

        The inlet is miswired, or the machine is unplugged as designed. Re-run the inlet continuity pattern, then Checkpoint #1. 10.5 · 10.23

      • The PSU was destroyed on first switch-on

        The 115/230 V selector was set for the wrong mains. There is no fix after the fact, which is why the selector is checked twice. 10.2 · 10.22

      • A controller or attached component died after power-on

        A Leviathan voltage-selection jumper was left in, or set to 5 V. Exactly two jumpers, Fan2 and Fan3, both at 24 V; Probe, Fan0 and Fan1 bare. With the Ch 14 Part H exhaust fan fitted, three: Fan0 at 24 V as well. 09.19 · 10.28

      • A driver died after a connector change

        A stepper or the Micro-Fit umbilical was moved with the power on. Power down for every connector change, because back-EMF kills drivers. Ch 13 Common mistakes

    • The meter sweep fails before power-on

      • A 24 V node beeps continuously against its ground

        A reversed ferrule or a stray strand. Find it before power-on: every node must read finite and rising, never 0 Ω. 10.74 · 10.29

      • A protective-earth row fails the bonding sweep

        A missing PE lead, or anodising under a washer. Scrape the anodising and re-land the lead. 10.77 · 10.16

      • The SSR reads short across LOAD 1 and LOAD 2 with nothing energised

        The relay is dead and the bed would be permanently live. Replace it, and do not power the machine. 10.21 · 10.78

    • A motor or an endstop misbehaves

      • STEPPER_BUZZ does nothing on one motor

        The enable or step pin, or no driver power. Check the pins, then the HV 24 V rail. 13.16 · 10.25

      • It buzzes but does not travel 1 mm

        The stepper coil pairs are transposed in the connector. Re-pin so each coil is a pair, power off first. 13.16

      • A motor runs the wrong way, or the wrong motor answers

        Wrong way is dir_pin polarity: add or remove the exclamation mark, RESTART, re-buzz. Wrong motor means the motors are on the wrong ports: power off, move the connector, power on. Never hot-swap a stepper. 13.16 · 10.40

      • X and Y both move but the toolhead travels diagonally

        A and B are swapped, or one is inverted. Upper block on the V2 chart means invert a dir_pin; lower orange block means physically swap A and B. 13.16

      • An endstop reads TRIGGERED untouched

        Wiring, not polarity: stock Voron endstops are normally closed to ground. Fix the wiring, and do not add an exclamation mark to silence it. 13.17

      • Homing overshoots into the frame

        The wrong build-size pair is uncommented; with none uncommented Klipper will not start. Prove the 350 edits are live on the running instance. 13.5 · 12.24

      • The toolhead cannot reach an endstop

        A rubber rail stopper is still on the rail, or the gantry is racked. Pull the stoppers, then square the gantry. 13.1 · 06b.14

    • Klipper will not start, or every pin is wrong at once

      • Every nhk pin behaves wrongly at once

        The Rev D config was loaded instead of the sbv2 file. Grep for nhk:PB8 before uploading; Rev D+ needs the sbv2 config. 12.21

      • Unable to open serial port

        The serial path was not pasted, or the board is not flashed. Re-read both paths and paste them. 12.23 · 13.4

      • Only one MCU enumerates, or none

        Read both serial IDs and confirm which is which before anything else. 12.11 · 12.20

      • The toolboard enumerates as rp2040

        That is a Nitehawk-SB V1, or the wrong firmware. Rev D+ must read stm32g0b1xx; the Rev D guide's rp2040 line is wrong for this kit. 00.5 · 12.12

      • The nozzle drives into the plate on G28

        home_xy_position was filled in with a guess. The placeholder failing is the interlock working: measure the real coordinate. 12.33 · 13.26

    • Heaters, fans and thermistors

      • A temperature climbs with nothing commanded

        A heater is energised through a wiring fault. Cut power at the switch and go back to Ch 10. Do not stand and watch it. 00a.12

      • The bed does not heat and the SSR LED is on

        The fault is on the mains side of the SSR. Check LOAD 1 and LOAD 2, and the bed L and N. 10.14 · 10.78

      • The bed does not heat and the SSR LED is off

        DC control polarity is reversed. Leviathan plus goes to SSR INPUT 3, minus to INPUT 4. 10.27 · 13.8

      • A thermistor reads a wild or jumping value

        A crimp, or a PH2.0 housing half seated or in the wrong header. Re-seat and check continuity: Rev D+ uses PH2.0, not the guide's XH2.5. 10.55 · 10.76

      • The chamber thermistor reads nothing

        It is plugged into a Leviathan TH port. Rev D+ reads it as nhk:PB2, on the toolboard's CT port. 10.39

      • A fan never starts

        Wrong port, wrong voltage jumper, or the keyed 2×5 toolhead header seated backwards. The header is keyed: if it will not drop in, it is backwards. 10.56 · 13.11

  • Calibration and the first print

    • QGL will not converge

      • Probed points range stalls or grows

        The gantry is racked. Square it in Ch 06b, which leaves A and B at a provisional tension, then re-run QGL. 13.34 · 06b.14 · 13.35

      • Possibly Z motor numbering is wrong

        The Z motors are on the wrong drivers. Recheck the map: Z0 front-left to STEPPER-0, Z1 rear-left to -1, Z2 rear-right to -2, Z3 front-right to -3. 13.33 · 10.43

      • Required adjustment is greater than max_adjust

        The gantry is too far out of level to correct in software. M84 with a hand under the gantry (it sinks when the Z motors release), level the gantry by hand against the frame, G28, retry. 13.33

      • Out of bounds, or a probe point cannot be reached

        The gantry is far from level, or gantry_corners is wrong. FIRMWARE_RESTART with a hand under the gantry (it sinks when the Z motors release), level the gantry by hand against the frame, G28, and confirm the 350 corners. 13.33 · 12.26

      • QGL passes but printed parts come out skewed

        QGL levels in Z only and says nothing about the X extrusion being square to Y. De-rack the gantry; QGL cannot detect racking. Ch 06b Common mistakes

    • The probe is unreliable

      • PROBE_ACCURACY deviation is high but stable

        The probe mount, cable strain, or a probe speed that is too fast. Check the retainer bracket is tight, then try a lower speed. 13.32 · 07.35

      • The values trend one way

        The frame is still expanding, or the Z pulley grub screws and belts are uneven. Soak longer, then check all four Z belts and the pulley set screws. 14.3 · 14.5

      • QUERY_PROBE is stuck open or stuck TRIGGERED

        Ground, signal or 24 V, a wrong probe pin, or a voltage-select jumper. Check the wiring first. 13.21 · 12.29

      • It triggers too early, or grazes the plate

        Too early means the probe sits too high in the retainer, or there is tape on the sensing face. Too late means it is mounted too low. Set it to trigger about 2 mm above the plate. 07.36 · 10.30

      • Z drops out of level between prints

        The Z pulley set screws are loose or off the flat. Threadlock, one screw on the flat, a proper hex driver. 02.20

    • The first layer is wrong

      • Right at the front, wrong at the back

        The mesh was taken before QGL, or taken cold. G28, QUAD_GANTRY_LEVEL, G28, BED_MESH_CALIBRATE, hot. 13.39

      • Featureless and glassy, or gappy and ridged

        Squish is set wrong, or the extrusion multiplier moved since it was set. Re-run the live-Z procedure and commit it with Z_OFFSET_APPLY_ENDSTOP. 13.42 · 14.21

      • The Z offset reverts after every restart

        Babystepping was never committed. Z_OFFSET_APPLY_ENDSTOP, then SAVE_CONFIG. Ch 13 Common mistakes

      • Every first layer is slightly under-squished

        Under-squish is expected after the paper test. Close it with live-Z at 13.42 and commit with Z_OFFSET_APPLY_ENDSTOP. 13.42

      • The whole mesh is offset by a constant

        bed_mesh was added without zero_reference_position. The Omron's z_offset is 0 by design, so pin the reference to bed centre. 12.34

    • The printed part is wrong

      • The cube is 0.1 to 0.3 mm oversize in X and Y

        ASA shrinkage and bulging, not an axis error and not a flow number. Confirm shrinkage and XY size compensation were 0 in the slice, and set the extrusion multiplier by eye on the top surface only. Voron parts need no other compensation. Never negative XY compensation. 14.11 · 14.20

      • A persistent X to Y size difference on the same cube

        A gantry-square problem. Go back to Ch 06b. 14.11 · 06b.14

      • Top surfaces have gaps and valleys, or pellets and ridging

        The extrusion multiplier is low or high. Run the 2 % pass, then the 0.5 % refinement. 14.19 · 14.20

      • Ringing after corners, even with input shaping saved

        max_accel was left at the stock 10000, and SAVE_CONFIG does not touch it. Set it at or below the lower per-axis suggestion, with margin. 14.15

      • Fine vertical ripple 0.5 to 2 mm apart on flat faces

        Belt-tooth engagement ripple, cosmetic and not ringing. It is not a tuning fault and input shaping does not fix it. Gen 2 belts

      • A cube corner delaminates along a layer line

        The chamber is too cold, or the part fan is too high. Set the chamber target and soak. 14.8 · 14.11

      • The shaper graph shows two or more widely separated peaks

        Usually mechanical: a loose backer, an under-tensioned belt, or a rail bolt in an end hole. Fix the machine before shaping over it; below 25 Hz on either axis is a build fault. 14.14

    • The extruder or the hotend

      • Molten plastic leaks at the heatsink on the first hot print

        The Revo strain relief was not bent clear, so the nozzle never hand-tightened fully. Bend the strain relief and re-seat the nozzle. 08.29

      • The extruder will not grip or tension filament

        The tension arm's M3×25 hinge pin was torqued instead of left as a hinge. Back it off: it is a hinge, not a fastener. 08.19 · 08.21

      • Extruded length does not match the commanded 100 mm

        rotation_distance is not set for this extruder. Run the 100 mm extrusion check. 14.7 · 13.40

      • PID tune of the hotend trips the temperature limit mid-run

        You are tuning at 260 °C against a max_temp of 270. Tune at 245 °C, or raise max_temp to 290 first. 13.30

      • The bed takes a long time to reach 110 °C

        heater_bed max_power is deliberately limited to protect the 355 mm cast plate. Wait, and do not raise it. Ch 14 Common mistakes

Motion — homing, axes, steppers, endstops

Symptom Likely cause Fix Owned by
STEPPER_BUZZ does nothing on one motor enable_pin / step_pin, or no driver power check the pins, then the HV / 24 V rail 13.16, 10.25
STEPPER_BUZZ buzzes but does not travel 1 mm stepper coil pairs transposed in the connector re-pin so each coil is a pair — power off first 13.16
A motor runs the wrong way dir_pin polarity add or remove ! on that stepper, RESTART, re-buzz 13.16
The wrong motor answers a buzz motors on the wrong ports power off, move the connector, power on. Never hot-swap a stepper 13.16, 10.40
G28 X drives the gantry down first Z stepper directions reversed fix the Z dir_pins before touching A or B 13.16
X and Y both move but the toolhead travels diagonally A and B swapped, or one inverted upper block on the V2 chart → invert a dir_pin; lower (orange) block → physically swap A and B 13.16
Homing overshoots into the frame the wrong build-size pair of position_endstop / position_max is uncommented prove the 350 edits are live 13.5, 12.24
An endstop reads TRIGGERED untouched wiring, not polarity — stock Voron endstops are N.C. to ground fix the wiring; do not add a ! to silence it 13.17, Ch 13 Common mistakes
X or Y endstop never triggers, cable is labelled X Stop / Y Stop LDO batch shipped with the wrong labels; needs re-pinning read the labels, then re-pin 10.31, 10.32
The toolhead cannot reach an endstop rubber rail stopper still on the rail, or the gantry is racked pull the stoppers, then square the gantry 13.1, Ch 06b
G28 → Move out of range: -10.000 -10.000 … [safe_z_home] home_xy_position still the placeholder measure the Z endstop coordinate and write it in 13.26, 12.33
0,0 does not land at the front-left corner of the plate endstop coordinates not defined against the plate re-run the 0,0 definition 13.25

Source: Ch 13 — What if · Ch 13 Common mistakes · Ch 10 Section 5 · Ch 12 Common mistakes

Z, QGL and gantry squaring

Symptom Likely cause Fix Owned by
QGL does not converge — Probed points range stalls or grows gantry racking square the gantry in Ch 06b (provisional A/B tension), then re-QGL 13.34, 06b.14, 13.35
QGL: "Probed points range is increasing. Possibly Z motor numbering is wrong" Z motors on the wrong drivers recheck the map: Z0 front-left → STEPPER-0, Z1 rear-left → -1, Z2 rear-right → -2, Z3 front-right → -3 13.33, 10.43
QGL: "required adjustment … is greater than max_adjust" gantry too far out of level to correct in software M84 with a hand under the gantry (it sinks when the Z motors release), level the gantry by hand against the frame, G28, retry 13.33
QGL "out of bounds" / cannot reach a probe point gantry far from level, or wrong gantry_corners FIRMWARE_RESTART with a hand under the gantry (it sinks when the Z motors release), level the gantry by hand against the frame, G28; confirm the 350 corners -60,-10 / 410,420 13.33, 12.26
QGL passes but printed parts come out skewed QGL levels in Z only — it says nothing about the X extrusion being square to Y de-rack the gantry; QGL cannot detect racking Ch 06b Common mistakes
PROBE_ACCURACY σ high but stable probe mount, cable strain, or [probe] speed too fast check the retainer bracket is tight; try a lower speed 13.32, 07.35
PROBE_ACCURACY values trending one way frame still expanding, or Z pulley grub screws / uneven Z belts soak longer; then check all four Z belts and the pulley set screws 14.3, 14.5
Probe samples exceed samples_tolerance the same causes — samples_tolerance: 0.006 is tight by design fix the cause; do not widen the tolerance 13.32
QUERY_PROBE stuck open or stuck TRIGGERED ground / signal / 24 V, wrong [probe] pin, or a voltage-select jumper check wiring first, then pin: !nhk:PC15 13.21, 12.29
Probe triggers too early (large gap at trigger) probe too high in the retainer, or tape on the sensing face lower it so it triggers ~2 mm above the plate; tape front and sides only 07.36, 10.30
Probe triggers too late, or grazes the plate probe mounted too low raise it in the bracket; it must clear the plate and the clips at every mesh point 07.36
Z drops out of level between prints Z pulley set screws loose or off the flat threadlock, one screw on the flat, proper hex driver 02.20, Ch 02 Common mistakes
Every Z dimension is silently wrong a 20T pulley fitted to a Z motor instead of a 16T count teeth — gear_ratio: 80:16 is baked into the config 02.27, Ch 02 Common mistakes

Source: Ch 13 — What if · Ch 06b Common mistakes · Ch 02 Common mistakes · Ch 14 Step 14.3

Extrusion and hotend

Symptom Likely cause Fix Owned by
Molten plastic leaks at the heatsink on the first hot print the Revo strain relief was not bent clear, so the nozzle never hand-tightened fully bend the strain relief, re-seat the nozzle 08.29, Ch 08 Common mistakes
Extruder will not grip or tension filament the tension arm's M3×25 hinge pin was torqued instead of left as a hinge back it off — it is a hinge, not a fastener 08.19, 08.21
CW2 main body cracked while tightening the motor plate the M3×25 pair over-tightened the manual's own advice is to bin the part and reprint 08.17, Ch 08 Common mistakes
Extruded length does not match the commanded 100 mm rotation_distance not set for this extruder run the 100 mm extrusion check 14.7, 13.40
Hotend heats when you command the bed, or vice versa thermistor pair or heater pair swapped swap at the board — power off first Ch 13 — What if
Thermistor reads a wild or jumping value crimp, or a PH2.0 housing half-seated / in the wrong header re-seat and check continuity — Rev D+ uses PH2.0, not the guide's XH2.5 10.55, 10.76
A temperature climbs with nothing commanded heater energised through a wiring fault cut power at the switch and go back to Ch 10 — do not watch it Ch 13 — What if, 00a.12
Bed does not heat, SSR LED on fault on the mains side of the SSR check LOAD 1 / LOAD 2 and the bed L and N 10.14, 10.78
Bed does not heat, SSR LED off DC control polarity reversed Leviathan + → SSR INPUT 3, − → INPUT 4 10.27, 13.8
PID tune of the hotend trips the temperature limit mid-run tuning at 260 °C against max_temp: 270 tune at 245 °C, or raise max_temp to 290 first 13.30, Ch 14 Common mistakes
Bed takes a long time to reach 110 °C [heater_bed] max_power is deliberately limited to protect the 355 mm cast plate wait — do not raise it Ch 14 Common mistakes

Source: Ch 08 Common mistakes · Ch 13 — What if · Ch 14 Common mistakes · Ch 10 Section 8

Electronics, power and comms

Symptom Likely cause Fix Owned by
Nothing powers on at all inlet miswired, or the machine is unplugged as designed re-run the inlet continuity pattern, then Checkpoint #1 10.5, 10.23
PSU destroyed on first switch-on 115/230 V selector set for the wrong mains there is no fix after the fact — the selector is checked twice for this reason 10.2, 10.22
A 24 V node beeps continuously against its ground reversed ferrule or a stray strand find it before power-on; every node must read finite and rising, never 0 Ω 10.74, 10.29
A PE row fails the bonding sweep missing PE lead, or anodising under a washer scrape the anodising; re-land the lead 10.77, 10.16
SSR reads short LOAD 1 → LOAD 2 with nothing energised the relay is dead; the bed would be permanently live replace it — do not power the machine 10.21, 10.78
Controller or attached components destroyed after power-on a Leviathan voltage-selection jumper left in, or set to 5 V exactly two jumpers, Fan2 and Fan3, both at 24 V; Probe/Fan0/Fan1 bare (three with the Ch 14 Part H exhaust: Fan0 at 24 V too) 09.19, 10.28
A fan never starts wrong port, wrong voltage jumper, or the keyed 2×5 toolhead header seated backwards check the port against the config; the header is keyed — if it will not drop in, it is backwards 10.56, 13.11
Only one MCU enumerates, or none firmware, serial path, or a USB cable read both serial IDs and confirm which is which 12.11, 12.20
The toolboard enumerates as rp2040 you have a Nitehawk-SB V1, not a V2 — or the wrong firmware Rev D+ must read stm32g0b1xx; the Rev D guide's rp2040 line is wrong for this kit 00.5, 12.12
A connector destroyed itself going in a PH2.0 housing forced into the wrong V2 header, or the fan adapter pressed in backwards if it needs force, it is wrong — read the silkscreen every time 10.55, Ch 08 Common mistakes
A driver dies after a connector change a stepper or the Micro-Fit umbilical moved with the power on power down for every connector change — back-EMF kills drivers Ch 10 Read first, Ch 13 Common mistakes
Umbilical or chain cable fails weeks after the build cables pulled tight in the drag chains loose in the chain, zip-tied at both ends of every chain 10.65, 10.66
The ESD ground path is missing or broken the V1 USB-adapter cover was fitted, hiding the grounding point fit usb_adapter_mount_partial_cover and the supplied grounding cable 10.57, 10.58
A short across the 24 V fan rail takes the controller with it the Nevermore bridge PCB was not metered before power meter the bridge PCB; the splicer must sit on its printed spacer 11.33, Ch 11 Common mistakes

Source: Ch 10 Checkpoint 10 and Common mistakes · Ch 09 Common mistakes · Ch 12 Common mistakes · Ch 11 Common mistakes

Symptom Likely cause Fix Owned by
First layer right at the front, wrong at the back meshed before QGL, or the mesh was taken cold G28 → QUAD_GANTRY_LEVEL → G28 → BED_MESH_CALIBRATE, hot 13.39, Ch 13 Common mistakes
First layer featureless and glassy, or gappy and ridged squish set wrong, or extrusion multiplier moved since it was set re-run the live-Z procedure and commit with Z_OFFSET_APPLY_ENDSTOP 13.42, 14.21
The Z offset reverts after every restart babystepping was never committed Z_OFFSET_APPLY_ENDSTOP then SAVE_CONFIG Ch 13 Common mistakes
Every first layer slightly under-squished expected after the paper test, before live-Z closes it close it with live-Z at 13.42 and commit with Z_OFFSET_APPLY_ENDSTOP 13.42
Cube is 0.1–0.3 mm oversize in X and Y ASA shrinkage and bulging, not an axis error or a flow number confirm shrinkage and XY size compensation were 0; set extrusion multiplier by eye on the top surface, never from the caliper; never negative XY compensation 14.11, 14.20
Cube's first layer is wider than its mid-height elephant-foot compensation wrong adjust in 0.05 mm steps 14.11
A persistent X − Y size difference on the same cube gantry-square problem Ch 06b 14.11, Ch 06b
Cube corner delaminates along a layer line chamber too cold, or part fan too high set the chamber target and soak 14.8, 14.11
Top surfaces have gaps and valleys, or pellets and ridging extrusion multiplier low / high run the 2 % pass, then the 0.5 % refinement 14.19, 14.20
Ringing / ghosting after corners, even with input shaping saved max_accel left at the stock 10000 — SAVE_CONFIG does not touch it set max_accel at or below the lower per-axis suggestion, with margin 14.15
Fine vertical ripple 0.5–2 mm apart on flat faces (VFA) belt-tooth engagement ripple — cosmetic, not ringing not a tuning fault; input shaping does not fix it print/00-slicer-setup.md
Mesh and Z offset are wrong for every print probed on a cold frame — the bed reaches temperature in minutes, the frame only when PROBE_ACCURACY stops trending heat soak before probing 13.31, Ch 14 Common mistakes
Shaper graph shows two or more widely separated peaks usually mechanical — a loose backer, an under-tensioned belt, a rail bolt in an end hole fix the machine before shaping over it; below 25 Hz on either axis is a build fault 14.14

Source: Ch 14 Parts D–F and Common mistakes · Ch 13 Common mistakes · print/00-slicer-setup.md

Printing the parts on the Core One+

Weeks 1–2, before the Voron exists. The fix is always in print/00-slicer-setup.md's "if out of spec" columns or a B00/B01 step — never a hand-edited override.

Symptom Likely cause Fix Owned by
PrusaSlicer shows a bare Prusament ASA @COREONE HF0.4, no "(modified)" on the print preset, or B00-P1 estimates far from 3 h 58 m the project's configuration did not load — wizard not run, HF nozzle variant not installed run the Configuration Wizard with the 0.4 HF nozzle ticked, reopen the project B00.0, 00-slicer-setup — one-time setup
Cube 0.1–0.3 mm oversize in X and Y shrinkage compensation or XY compensation not zero, or flow high confirm 0 % / 0, then extrusion multiplier down in 1 % steps — never negative XY compensation Gate A, B00.5
Cube Z off, or the first layer wider than mid-height squish (Live Adjust Z) or elephant-foot compensation Z: fix the sheet/glue/nozzle seat, not a saved nudge — the Core One+ keeps none; first layer: elephant-foot in 0.05 mm steps B00.4, Gate A
First layer glassy and featureless, or gappy and ridged, on the Core One+ the loadcell zeroed Z on a sheet that is not seated, a lumpy glue film, or a nozzle not fully seated fix the cause; a Live Adjust Z nudge is per-print and not saved B00.4, 00-slicer-setup — calibration item 3
Cube corner delaminates at the snap test chamber too cold or part fan too high drop min/max fan to 0 / 15 %, keep the 40 °C chamber gate Gate A
A long flat part lifts at the ends partway through glue film missing or old, chamber started cold, or a reprint without its brim sheet per §Print sheet; chamber gate; per-object brim on the reprint — never the global setting Print sheet, Orientation & brim
The preview shows a brim on flat grills or clips that should have none the global brim was set by hand clear Print Settings → Skirt and brim; brims live per object in the committed projects Orientation & brim, B02.4
625-2RS or F695 bore too tight or too loose flow, or shrinkage compensation not zero — the seats are drawn for 100 % tight → extrusion multiplier −1 % and reprint; loose → confirm 0 % shrinkage; never enlarge with compensation Gate B, B01.7, B03.4
Heat-set boss bulges or the insert sits crooked iron too hot or pushed too fast — technique, not the slicer practise on the coupon until two in a row are flush Gate B, 00.13
The spool runs out mid-plate predicted once, on B09-P1 let the runout sensor pause, load the next spool, resume — never plan one on a bearing-seat plate Spool ledger, When the printer stops
The power went out mid-plate — resume only if the printer offers it and the part is still firmly stuck; otherwise clear the sheet and reprint the plate When the printer stops
A "bed not aligned" / Z-alignment prompt at a plate start on this machine usually loadcell noise or a dirty tip, not a moved bed cancel, run the printer's Z alignment, start again; if it returns, brush the hot tip clean and check under the sheet When the printer stops
The nozzle taps the same probe point again and again ooze on the tip, or heater noise on the loadcell cancel, brush the hot tip clean, restart the plate; a second loop stops the run When the printer stops
Spaghetti: a part came loose mid-plate glue film, brim or a cold chamber start stop, cool, clear the sheet, fix the cause, reprint the whole plate When the printer stops, Print sheet

Source: print/00-slicer-setup.md — Calibration sequence · B00 Common mistakes · B01 Common mistakes · Prusa KB — Live Adjust Z

Mechanical — noise, binding, play

Symptom Likely cause Fix Owned by
A tight spot near one end of X travel a rail is not centred on its extrusion re-centre and re-tighten from the middle outward 05.44, 05.33
Stiffness that grows steadily toward one end the gantry is racked square it in Ch 06b. Do not loosen rails to make it feel better 05.44, 06b.14
A Z carriage has a tight spot the whole length rail screws tightened from one end, bowing the rail back them off and re-tighten centre-outward 02.07, Ch 02 Common mistakes
A carriage is notchy or gritty and gets worse the rail was installed dry, or grease was left on the rail surface flip-and-pack needs the back of the rail — it comes off, or it wears out 00.19, Ch 00 Common mistakes
Grease has gone milky and lost film strength packed before the IPA fully evaporated strip, dry properly, re-pack 00.18, Ch 00 Common mistakes
Belt noise that tension changes do not fix crushed idler pockets from over-tightened 20T idler bolts those bolts only locate the idler — they thread into plastic Ch 05 Common mistakes
A belt runs clean at one end of travel and rubs at the other a half-twist somewhere in a long run sight down each straight run; teeth must face the same way at both ends 07.29, Ch 07 Common mistakes
A belt shreds against a flange a bearing pair fitted flange-to-flange or flange-in open the stack; the plain faces must meet 04.07, Ch 04 Common mistakes
The A and B belts rub against each other pulleys at the same height, or the B pulley fitted hub-down A = 16.5 mm hub down, B = 6.5 mm hub up, re-checked with the jig 04.24, 04.33
A and B tension will not converge unequal belt lengths, unequal tail protrusion, or a belt rubbing cut both together; equalise the tails; inspect every idler 07.33, 07.08
Belt frequency reads far too high and will not come down you are reading a harmonic, not the fundamental take the lowest peak, three plucks, in a quiet room, over a measured 150 mm span 07.31, 07.30
The plate tacos on the first heat to 110 °C all four bed bolts were tightened; the plate must float on three one bolt only — the plate is meant to expand 03.17, Ch 03 Common mistakes
A bed bolt strips its T-nut on first tighten the manual's M3×16 barely engages through a 10 mm plate plus spacer use the M3×20 Ch 03 Common mistakes
A drive-frame post strips and the frame will not hold M5×30 BHCS torqued into plastic stop at closed-and-snug; a stripped post means a reprint Ch 04 Common mistakes
A skirt or COB mount is bowed and will not sit flat warped print, caught after assembly instead of at the flat-reference check check parts against the flat reference as they come off the plate print/B07, print/B08
A side panel is scored by the gantry 1 mm foam tape used on the sides instead of 3 mm 1 mm on back and top, 3 mm on the sides — the 3 mm is a standoff 11.56, Ch 11 Common mistakes
The Clicky-Clack door racks, or the latch will not catch loose M5×45 dowel fit, or the door is hung wrong at the hinges re-hang at the hinges — the latch is almost never the problem 11.62, Ch 11 Common mistakes

Source: Ch 05 Step 05.44 · Ch 00, Ch 02, Ch 03, Ch 04, Ch 05, Ch 07, Ch 11 Common mistakes

Software and config

Symptom Likely cause Fix Owned by
Every nhk: pin behaves wrongly at once leviathan-printer-rev-d.cfg loaded instead of the -sbv2 file grep for nhk:PB8 before uploading; Rev D+ needs the -sbv2 config 12.21, Ch 12 Common mistakes
mcu 'nhk': Unable to open serial port serial path not pasted, or the board is not flashed re-read both paths and paste them 12.23, 13.4
Katapult is gone and the board will not flash bootloader offset omitted in make menuconfig recover over DFU with the board buttons, then re-flash with the right offset 12.16, Ch 12 Common mistakes
menuconfig settings do not match the board following the V1.3 Leviathan guide on a V1.2 board (or the reverse) read the silkscreen and the serial ID before menuconfig 12.13, Ch 12 Common mistakes
Both boards flashed twice, for no reason MCU firmware built before the Update Manager ran update the host first, then flash Ch 12 Common mistakes
Unknown command:"BED_MESH_CLEAR" at the end of a print no [bed_mesh] section add it — a warning, not a failure, but you have no mesh 12.34, 13.38
The whole mesh is offset by a constant [bed_mesh] added without zero_reference_position the Omron's z_offset is 0 by design; pin the reference to bed centre 12.34, Ch 12 Common mistakes
The nozzle drives into the plate on G28 home_xy_position filled in with a guess -10,-10 failing is the interlock working — measure the real coordinate 12.33, 13.26
Interface reports X/Y travel of 250, not 350 the 350 mm config edits are not live check the running instance, not the file on disk 13.5
The chamber thermistor reads nothing plugged into a Leviathan TH port Rev D+ reads it as nhk:PB2 — it belongs on the toolboard's CT port 10.39, Ch 10 Common mistakes
The probe reads nothing on the Leviathan Z-PROBE header on a Nitehawk build the probe lives on the toolboard's PROBE port the stock config's comment says otherwise and the comment is wrong Ch 10 Common mistakes, 12.29
The filter fan cannot be commanded from a macro or the slicer LDO's stock config declares FAN3 as a [heater_fan] slaved to the bed this manual replaces it with fan_generic 12.32, 11.41
Homing is lost after every SAVE_CONFIG SAVE_CONFIG restarts Klipper re-G32 after each one Ch 14 Read first

Source: Ch 12 Common mistakes and Checkpoint 12 · Ch 13 Step 13.4 · Ch 10 Common mistakes

Order-of-operations traps

These have no symptom until they are expensive. They are in the chapters' Common mistakes lists because you cannot debug your way out of them — you can only avoid them.

Trap What it costs Owned by
Fitting a rail before greasing it the rail comes off again, or runs dry for the life of the machine 00.19, 02.05
Missing a heat-set insert before a part is closed six M3×40 out and the shaft assembly lifted (Z drive); a gantry teardown (XY joint) 00.16, 02.04, 08.03
Fitting the titanium backers after the gantry is built ~3 h teardown — their T-nut slots are capped by the drive and idler frames 05.16, Ch 05 Common mistakes
Using a rail's end hole the rail comes off and goes back on — the end holes are where the p.89–90 / p.102 T-nuts live 00.22, 05.33
Skipping the reserved T-nuts at p.90 Ch 06's Z joints and Ch 10's chain hardware have nowhere to bolt to 05.13, Ch 05 Common mistakes
Skipping the deck supports until Ch 11 the frame has to come partly apart — the deck cannot be lifted once the gantry and electronics are in 02.14, Ch 02 Common mistakes
Resolving the deck thickness from the documents LDO's guide says 4 mm and LDO's BOM says 3 mm — only the caliper settles it, and B01 needs the answer 00.4, 02.12
Torquing the frame corner by corner as you go whatever error was there is locked in; the mallet cannot fix it afterwards 01.12, Ch 01 Common mistakes
Treating Ch 07's belt tension as final Ch 06b releases A/B tension completely as its first move 07.33, 06b.6
Setting Z offset or bed mesh before squaring the gantry everything measured before Ch 06b is scrap 13.34, Ch 13 Common mistakes
Closing the bay or fitting panels before Checkpoint #1 an unverified mains bay behind a bottom panel, and an hour to undo 10.71, Ch 11 Common mistakes
Running SHAPER_CALIBRATE before the first good print or final belt tension the result is stale before you use it; the same applies to pressure advance 14.13, Ch 14 Common mistakes
Building Klicky because the parts are on the bench the kit's config, wiring and cable are all for the inductive probe 08.54, B06.4, Ch 08 Common mistakes
Starting B01 or B03–B06 on Gate A alone 58.5 h and 763 g of bearing-seat and shaft-bore parts printed against an unverified bore fit — Gate B's bore and insert rows run early on the ordered hardware, so there is nothing to wait for B00.7, Gate B
Nudging Live Adjust Z on every plate instead of fixing the sheet the Core One+ does not save the nudge; the first plate you forget lifts at hour 2 B00.4

Source: the Common mistakes sections of Ch 00, 01, 02, 04, 05, 07, 08, 11, 13, 14, B00

Not covered here — where to ask

If your symptom is not in the tables above, this manual does not have an answer for it and you should ask rather than improvise. The three lifelines were joined in Step 00.31; this is what each one is for.

Where Use it for Link
Fabreeko Discord missing, wrong or damaged parts; anything vendor-specific; your batch sheet discord.gg/NV8Y6bcerP
Voron Discord, #voron_2_questions general 2.4 build and tuning questions. The server also runs a general help channel — check its channel list; Step 00.31 names only #voron_2_questions discord.gg/voron
#ldo_motors (inside the Voron Discord) anything Rev D / Rev D+ specific, and the channel LDO's Build Notes direct corrections to channel link
Klipper Discourse Klipper itself — config, firmware, macros, shutdowns community.klipper3d.org

Put all five of these in the question, or you will spend a day getting asked for them:

  1. Kit identity — the serial from carton 1, formatted V2-YYMMDD####, and that it is an LDO Voron 2.4 R2 Rev D+, 350 mm with a Nitehawk-SB V2 toolboard. Rev D+ is why half the published answers will not apply to you.
  2. Where you are — the chapter and step number from this manual, plus the corresponding official manual page or LDO guide section from that step's Source: line. That turns "it binds" into a place on a drawing.
  3. The config file name you actually loaded — leviathan-printer-rev-d-sbv2.cfg, not leviathan-printer-rev-d.cfg. Say which, because it is the single most common wrong assumption in a Rev D+ thread.
  4. klippy.log, complete and unmodified. Klipper's own instruction: "Do not modify the log file in any way; do not provide a snippet of the log. Only the full unmodified log file provides the necessary information." It lives at ~/printer_data/logs/klippy.log; zip it before attaching.
  5. A photo of the assembly you are asking about — and for anything mechanical, one photo of the working side too.

Source: Ch 00 Step 00.31 · Ch 00 Step 00.2 · Klipper — Contact · Ch 12 Step 12.21

Next

Ch 16 — Glossary: every term this manual assumes you already know, with the chapter where each one first matters.