# Hardware, spare parts and self-builds


**Draft, not yet verified on hardware.**

Wear, heat and noise, spare parts, the controller board and the open design files of the SeedHammer II on stock firmware v1.4.3. The SH II is sold out and no longer produced.

<p class="alert alert-warning">Seed words are typed on the machine only and never pass through a phone, a computer or a chat assistant. A descriptor holds no secret and reveals every address of the wallet.</p>

## What you need {#requirements}

- The USB-C power cable unplugged before you touch any plug inside the machine.
- The hardware line from the start screen, for example "Hardware: v1.5"; quote it when you ask for a spare part.
- For a board swap: a computer to upgrade the new board ([Firmware upgrade](/doc/manual/firmware-upgrade)).
- For a self-build: the <a href="https://github.com/seedhammer/hardware" target="_blank">hardware repository</a>.

![Start screen with the firmware and hardware version](/static/img/hardware-and-spares-01.webp)
<!-- capture: II screen, start screen "Backup Wallet", version lines "Firmware: v1.4.3" and "Hardware: v1.5", Go test harness per research/device-screen-map.md section 4 -->

## What wears, and how long it lasts {#wear}

| Item | Figure | What to do |
| --- | --- | --- |
| Machine | Hundreds of plates, a design target; SeedHammer's own runs had not reached it by 2025-07. | |
| Carbide needle tip | 500 to 1000 plates without dulling (unverified). | |
| Steel on the tip | Can build up. | Scrape it off. Put a drop of light oil on the plate before engraving. |
| Sticking needle, wobbly text, fading words, homing errors | Mechanical faults, separate from wear. | [Engraving quality](/doc/manual/engraving-quality#mechanics) |

## Heat and noise {#heat-noise}

The "Engrave Plate" screen warns before every job: "The process is loud, use hearing protection."

| Item | Figure | What to do |
| --- | --- | --- |
| Power while engraving | Not much above 30 W on a meter sampling about once a second (unverified). Short peaks can be far higher. | Size the supply by [Choose the power supply](/doc/manual/power-and-first-start#power), never by this figure. |
| Box lined with sound-deadening mat | Quieter; in one such box the hammerhead reached about 90 °C (unverified). | Let it cool between runs. |

## Spare parts {#spares}

Every part except the hammerhead is a standard part or can be made from the repo files.

| Part | Where it comes from | In the repo |
| --- | --- | --- |
| Hammerhead (electric coil, carbide tip, 2-pin plug) | SeedHammer; stock unverified. A look-alike marketplace head was pneumatic. | <a href="https://github.com/seedhammer/hardware/blob/main/specs/hammerhead.pdf" target="_blank">specs/hammerhead.pdf</a> |
| Controller board | SeedHammer, in small batches (unverified), or made from the repo files. Production boards: made and assembled by JLCPCB. | <a href="https://github.com/seedhammer/hardware/tree/main/mainboard/pcb" target="_blank">mainboard/pcb</a> |
| Display | ER-TFT035IPS-6 with capacitive touch, from buydisplay.com. The resistive-touch variant does not work with the firmware. | <a href="https://github.com/seedhammer/hardware#lcd" target="_blank">README</a> |
| Stepper motors, bearings, rods, lead screws, belts, pulleys, bushings | Standard parts, in the parts list. | <a href="https://github.com/seedhammer/hardware/blob/main/shii/bom/bom.csv" target="_blank">shii/bom/bom.csv</a> |
| Screws and nuts | ISO and DIN standard fasteners. | <a href="https://github.com/seedhammer/hardware/blob/main/shii/bom/fasteners.csv" target="_blank">shii/bom/fasteners.csv</a> |
| Frame and other custom parts | FDM-printed, CNC-milled or lathe-machined from the STEP files; the parts list gives filament, layer and infill for printed parts. | <a href="https://github.com/seedhammer/hardware/tree/main/shii/cad" target="_blank">shii/cad</a> |
| Plates | [Plates](/doc/manual/plates) | |

## Take out the controller board {#board}

The controller board carries the microcontroller, USB-C power negotiation, stepper drivers, hammerhead supply, display connection and NFC reader.
It unplugs, so you can keep, destroy or swap it without taking the frame apart.

- Unplug the USB-C power cable from the machine.
- Disconnect the plugs from the board.
- Pull the right side of the board out.
- Slide the left side free without straining the USB-C socket.

The repo design has two 4-pin motor plugs (`J1` X, `J5` Y), the 2-pin solenoid plug (`J8`), the display's flat cable and two 3-pin connectors; the count on a shipped machine is unverified.

![Controller board in the machine with its plugs](/static/img/hardware-and-spares-02.webp)
<!-- capture: photo, SH II controller board in place, every plug labelled (two 4-pin motor plugs, 2-pin engraving solenoid plug, display flat cable, any other connector), USB-C socket and the right and left edges marked -->

![Controller board out of the machine](/static/img/hardware-and-spares-03.webp)
<!-- capture: photo, controller board removed, both faces, firmware button with its printed label, reset button, display ribbon connector locks -->

Board buttons: [the firmware button](/doc/manual/firmware-upgrade#button).

### Fit a board {#fit-board}

- Upgrade a replacement board before use: [Firmware upgrade](/doc/manual/firmware-upgrade).
- Fit the board in the reverse order of removal (order and fixings on a shipped machine unverified).
- Push each plug fully home.
- Connect the power supply. The start screen "Backup Wallet" shows "Firmware: v1.4.3" bottom right.

### Test without wasting a plate {#test}

v1.4.3 has no dry-run setting.

- Unplug the engraving solenoid: [Unplug the engraving solenoid](/doc/manual/engraving-quality#unplug).
- Send a public test descriptor and watch the job run without strikes. Never test with a real seed.

## Keep, swap or destroy the board {#board-security}

You never have to replace the board: the firmware writes nothing durable.
When to keep, swap or destroy it: [Lending, selling and travel](/doc/manual/security-faq#lending); what each chip holds: [What the machine keeps](/doc/manual/security-faq#storage).

## Build or repair from the open files {#self-build}

The design files in the hardware repository are public domain.

| Item | Detail |
| --- | --- |
| Board | KiCad schematic and PCB in `mainboard/pcb`; the board's components are listed only there. The README explains how to generate the production files and lists the JLCPCB settings. Its command says `cd pcb`; run it in `mainboard/pcb`. |
| Mechanics | STEP files in `shii/cad`; drawings `shii/cad/clampsled.pdf`, `shii/cad/nema17-stepper.pdf`, `specs/hammerhead.pdf`. Parts-list row of the clamp sled drawing unverified. |
| Parts lists | `shii/bom/bom.csv` (machine parts by assembly group), `shii/bom/fasteners.csv` (screws and nuts). The counts differ between the two in places. |
| Firmware | Install a release ([Firmware upgrade](/doc/manual/firmware-upgrade)) or build from source and compare ([Rebuild a release](/doc/manual/security-faq#reproduce)). On a repo-built board a release file boots and shows " (UNLOCKED)" (unverified). |
| Kit, assembly guide | None. No assembly instructions are planned for the SH II. |
| A computer instead of the board | Not possible: the board also handles power, motors and hammerhead. |
| Early boards | Can differ: board parts changed during production, and the repo holds the latest design. |

## If it does not work {#troubleshooting}

| Symptom | Cause | Fix |
| --- | --- | --- |
| The screen stays black. | No supply offer of 20 V to 28 V at 3 A or more. | [Power faults](/doc/manual/power-and-first-start#troubleshooting) |
| The screen is garbled after the board was out. | Loose display ribbon. | [Reseat the ribbon](/doc/manual/troubleshooting#screen) |
| The head moves but does not strike, or stops striking partway. | Loose 2-pin engraving solenoid plug, sticking needle, or weak supply. | [Needle and cables](/doc/manual/engraving-quality#needle) |
| "Engraving failed." with "Error: stepper: homing timed out". | Loose pulley set screw or weak supply. | [Pulleys](/doc/manual/engraving-quality#pulleys) |
| The start screen shows " (UNLOCKED)". | Secure boot is off, or a boot key other than the SeedHammer key is valid. | If you did not add a key: [Read the lock mark](/doc/manual/security-faq#unlocked) |

<!--
bench-checks:
  - [ ] Board removal and refit on a shipped SH II with photos 02 and 03: which plugs and how many (company statement, SYNTHESIS Q45: three; repo design: J1 X motor, J5 Y motor, J8 solenoid, plus the LCD FPC and two 3-pin wafers per the security-faq bench note), right side out then left side, USB-C clearance, tools or fixings, refit order. The body gives the repo design and marks the shipped count, refit order and fixings unverified (harmonized 2026-10-10 with security-faq; edit pass 2026-10-10 moved the "Check:" sentences here)
  - [ ] Display: does it come out with the board, or must its ribbon be released at the connector locks first; this also decides whether a board swap replaces the LCD driver's OTP area (TEAM 1447); the body no longer raises the question
  - [ ] Black screen after the board was out on a 28 V supply: can a loose display ribbon cause it (sources cover only a garbled screen, TEAM 634 635); if yes, add it to the black-screen row after the power cause
  - [ ] Firmware button label on a shipped board ("Hold button while connecting the USB cable to update firmware" is the repo silkscreen next to SW1, net USB_BOOT; SW2 is RESET); owner of the label text is firmware-upgrade#button, this page links there (SYNTHESIS F8)
  - [ ] Company replacement board as delivered: does it start the machine before the firmware upgrade, what it shows before and after, which hardware version it reports ("Hardware: v1.4" or "v1.5", or an OTP value; same question for shipped units) (only source is team advice to upgrade, TEAM 680; the troubleshooting item was removed until this is known)
  - [ ] v1.4.3 job on a hardware v1.5 board with J8 unplugged (TEAM 1092 advice dates from 2026-04-10, before v1.4.3): "Engraving completed successfully." or "Engraving failed." with which error; owner of the dry-run steps is engraving-quality#unplug
  - [ ] v1.4.3 with a motor plug out: which error ("stepper: homing timed out", "stepper: x-axis blocked", "stepper: y-axis blocked"); add a troubleshooting row once known
  - [ ] Power-meter trace of a full plate on v1.4.3 at 28 V (average and peak); only source is one owner's recollection of 1 s samples (message 1464), marked unverified in the #heat-noise table. engraving-quality no longer states "about 30 W on average"; it links to #heat-noise here (harmonized 2026-10-10)
  - [ ] Owner-only figures, sources moved out of the body by the edit pass and marked unverified there: hammerhead about 90 °C in a box lined with sound-deadening mat (one owner; measure on a bench run or drop the row); carbide tip life 500 to 1000 plates (one long-term owner's estimate; ask the company or log plates per tip)
  - [ ] Test plate in the box of v1.4.3-era units (TEAM 1038 was hedged); keep in step with plates.md and engraving-quality.md
  - [ ] Release UF2 on a board built from the repo files: boots, start screen "Hardware: v1.5 (UNLOCKED)"; the body states it in the self-build table, marked unverified
  - [ ] Ask the company: hammerhead and board stock (TEAM 1812 calls the engraving head the main supply-chain unknown; board "in small batches" is marked unverified in the spares table; the 2026-10-10 fix pass dropped the "possibly" hedge and the "estimate" tag on tip life); does a current hammerhead fit early boards; is there a published plate-life figure beyond the 2025-07 "hundreds" target (TEAM 176); the no-assembly-instructions statement for the SH II is a company statement
  - [ ] Repo BOM linked, not copied: shii/bom/bom.csv and shii/bom/fasteners.csv, on main since bffcec2 (committed 2026-08-31, "shii: separate SHII files to subdirectory and add bill of materials"), a rebased copy of ed6b2a5 (committed 2026-08-23, not on main). Hardware PR #3 ("Add draft BOM (hardware parts list)", a community BOM.md with vendor links) was closed unmerged on 2026-08-27, after the company's lists existed, so the page links the repo lists instead of the PR
  - [ ] Reconcile bom.csv against fasteners.csv and the STEP files (main 9d187f7): M5 self-locking nuts 17 vs 16, M5x20 countersunk 4 vs 2, M5x16 countersunk (2 in bom.csv) missing from fasteners.csv, M4x120 grub screw only in fasteners.csv
  - [ ] Which BOM row clampsled.step and clampsled.pdf are: bom.csv lists "1. Headsled" as CNC-milled aluminium 7075 and "0. Sled" as FDM-printed PETG, while TEAM 2020 calls clampsled the x-axis sled and the only CNC part; ask the company or read the drawing title block
  - [ ] Recheck every repo path before publication (files moved into shii/ and mainboard/ in 2026-08 and 2026-09, b65448e; README still says "cd pcb") and every internal link (security-faq, power-and-first-start, engraving-quality, firmware-upgrade, plates, troubleshooting)
  - [ ] Reproducible build: the page no longer says "reproducible bit for bit"; it links to security-faq#reproduce, which quotes the README's hedged wording and holds the bench item
sources: research/BRIEF.md; research/device-screen-map.md sections 1.1 (USB-PD 20 to 28 V at 3 A or more, rebootIntoBOOTSEL leaves the screen black, platform_sh2.go:206-224, 428-441), 1.2 (HardwareVersion "v1." + board version), 1.7, 1.8 (firmware ea4b65b gui/gui.go:2255, 2268, 2370-2373; cmd/controller/engraver.go:30-34, 61-64, 200, 284-286, 346; cmd/controller/platform_sh2.go:536); github.com/seedhammer/hardware main as of 2026-10-10 (README.md, shii/bom/bom.csv, shii/bom/fasteners.csv, specs/hammerhead.pdf, shii/cad incl. clampsled.pdf and nema17-stepper.pdf, mainboard/pcb/mainboard.kicad_sch and mainboard.kicad_pcb for J1 J5 J8 SW1 SW2 and silkscreen, issues 1 and 2, PR 3, commits ed6b2a5 bffcec2 a117cc0 b65448e); firmware README (hardware link, reproducible builds); https://seedhammer.com/faq (LCD ribbon reseat); https://seedhammer.com/doc/manual/firmware-upgrade; harvest Q42 Q43 Q45 (also Q38 Q39 Q40 Q41 Q44), SYNTHESIS C 2025-08-16 and 2026-08-22, SYNTHESIS D rows for display cable, head stops striking and homing, SYNTHESIS F10 (voltages, not watts); evidence ids 176 1564 1566 1542 1464 1483 1485 655 680 694 1092 1038 1447 1543 1570 1571 1812 2020 634 635 26 339 122 123; manuals/REVIEW-wave1.md sections 2 to 4 (harmonized, see manuals/HARMONIZE-wave1.md); edit pass 2026-10-10 per manuals/EDIT_BRIEF.md (before copy in manuals/.before/hardware-and-spares.md)
-->