---
title: HBOX Watchdog v3 PROD — Assembly BOM Split
project: Project Drogheda
date: 2026-07-05
tags: [project-drogheda, hardware, pcb, assembly, jlcpcb, bom]
status: Board routed, DRC fab-clean — assembly reference for JLCPCB PCBA order
---

# HBOX Watchdog v3 PROD — Assembly BOM Split

Audit of the routed board (`kicad/hbox-watchdog-v3-PROD.kicad_pcb`, 126 footprints)
for the JLCPCB assembly order. Three buckets: **(A)** what JLC solders onto the
board, **(B)** the plug-in modules that sit on top (you install), and **(C)** what
lives off-board and connects through the JST harness.

| Bucket | Count | JLC assembles? |
|---|---|---|
| A. On-board parts (SMD + THT) | 103 parts + 12 connectors + 5 sockets | **Yes** |
| B. Plug-in modules (on top) | 3 modules | No — you install |
| C. External via JST harness | wired to 12 connectors | No — off-board |
| Fab features (2 test points, 4 mounting holes) | 6 | n/a |

---

## A. Assembled by JLC — on the PCB

### A1 · SMD parts (standard PCBA — 98 parts)

| Qty | Value | Package | Refs |
|---|---|---|---|
| 10 | 10k | R0603 | R2, R5, R6, R7, R8, R41, Rigb, Rled, Rrp, Rtp |
| 8 | 100k | R0603 | R20, R56, R57, R58, Ren1, Rfreq, Rfreq2, Rgs |
| 7 | 100nF | C0603 | C5, C7, C9, C11, C24, Cu3, Cu4 |
| 5 | LED | LED0805 | D1, DB1, DB2, DB3, DB4 |
| 4 | 1k | R0603 | R1, R3, R40, Rts |
| 4 | 330R | R0603 | RB1, RB2, RB3, RB4 |
| 3 | SS34 | D_SMA | D2, Dbk, Dbk2 |
| 3 | 22uF | C0805 | C35, C40, C41 |
| 3 | 100k/1% | R0603 | R52, R54, R60 |
| 2 | MP1584EN | SOIC-8-EP | U2 (fan buck), U7 (modem buck) |
| 2 | 2.2nF | C0603 | Ccomp, Ccomp2 |
| 2 | 100R | R0603 | Rg, Rig |
| 2 | 10uF | C0805 | C30, C34 |
| 2 | 4.7k | R0603 | R30, R31 |
| 2 | 40.2k | R0603 | Rcomp, Rcomp2 |
| 2 | MMBT3904 | SOT-23 | Q5, Q6 |
| 2 | 10nF | C0603 | Cbst, Cbst2 |
| 2 | AO3400A | SOT-23 | Q2, Q4 |
| 2 | 10k/1% | R0603 | R42, R55 |
| 2 | 47uF | C1210 | C32, C33 |
| 1 | **LTC4040EUFD** | QFN-24 | U6 (backup-supply/charger) |
| 1 | AO4406A | SOIC-8 | Q7 |
| 1 | AO3401A | SOT-23 | Q1 |
| 1 | IRFR5305 | TO-252 | Q10 |
| 1 | BZX84C15 | SOT-23 | DzG |
| 1 | BAT54 | SOD-123 | D5 |
| 1 | 1N4148W | SOD-123 | D6 |
| 1 | SMBJ33A | D_SMB | D10 |
| 1 | **SHT40-AD1B** | DFN-4 | U3 (humidity/temp) |
| 1 | **TMP102** | SOT-563 | U4 (temp) |
| 1 | 8mR/1% | R1206 | RS1 (current sense) |
| 1 | PPTC 3A | Fuse1812 | F1 |
| 3 | 2.2uH / 10uH / 10uH-2A | SRU8028 8×8 | L6, L2, L7 |
| 1 | 22uF/50V | C1210 | C22 |
| 1 | 22uF/16V | C0805 | C23 |
| 1 | 2.2uF | C0603 | C31 |
| — | *(single-value R's)* | R0603 | Ren2 20k, Rdfu 22k, R21 19.1k, R50 825R, R51 287k, R53 499k, R61 31.6k |
| 4 | jumpers | SolderJumper | JP1 (0R), JP2 (F2), JP3 (F1), JP4 (F0) |

### A2 · Through-hole parts (THT — JLC "through-hole assembly" surcharge, or hand-solder)

| Ref | Part | Note |
|---|---|---|
| K1 | Omron G5V-1 DC5 relay | Modo-B fail-safe bypass |
| SW1 | 6 mm push (RESET) | |
| C3, C10, C43 | Radial electrolytics (47µF, 47µF/50V, 100µF) | |

### A3 · Connectors & module sockets (THT — soldered to board)

| Ref | Part | Purpose |
|---|---|---|
| P1 | Phoenix MKDS 1.5-5 (5-pos terminal) | GX16 machine power in |
| P2, P8, P10, P11, P12 | JST-XH 2-pin | see bucket C |
| P4, P13 | JST-XH 3-pin | |
| P3, P5, P6 | JST-XH 4-pin | |
| H3 | 1×3 pin header | USART1 reserved |
| **J1, J2** | 1×20 female 2.54 | **Blackpill socket** |
| **J7, J8** | 1×10 female 2.00 | **4G XBee socket** |
| **MOD1** | Arduino-UNO-form female headers | **simpleRTK2B Pro socket** |

> ⚠️ **Confirm before ordering:** engineering notes flag **P3 / P13 / H3 as DNP**
> (Modo-B + K1 NC bypass makes them redundant), but they are **not** marked DNP in
> the board file — so JLC would populate them. Decide per-connector.

---

## B. Plug-in modules — mounted ON TOP (you install, NOT in the JLC order)

These are complete boards that seat into the sockets above. Do **not** add them to
the JLC BOM — they're hand-fitted after the PCBA arrives.

| Module | Seats into | Notes |
|---|---|---|
| **simpleRTK2B Pro** (ZED-F9P) | MOD1 (Arduino headers) | GNSS RTK receiver |
| **STM32F411 Blackpill** | J1 + J2 (2×20) | watchdog MCU |
| **4G NTRIP Master** (XBee LTE) | J7 + J8 (2×10, 2 mm) | modem, 3V3 socket |

---

## C. External — connected via the JST harness (NOT on the board)

Everything that plugs into the edge connectors and lives outside the HBOX (or in the
cabinet). Wire per the harness pinout (`harness-connector-pinout.md`).

| Conn | Wires to (external) | Key pins |
|---|---|---|
| **P1** GX16-5 | Machine power + ignition from the cabinet | 1 = 24V_IN ⚡, 3 = IGN_IN, 2 = GND |
| **P2** 5V-IN | Mean Well SD-15B-05 5 V supply (VEH5V rail) | 1 = VEH5V ⚡, 2 = GND |
| **P3** RTK2B-UART1 | RTK2B UART1 tap (GNSS TX/RX) | 1 = SW_5V ⚡, 3 = GNSS_TX, 4 = GNSS_RX |
| **P4** BATT | 1S4P 12 Ah pack + NTC | 1 = BAT_PLUS ⚡, 3 = NTC, 2 = GND |
| **P5** TEMP_PROBE | External I²C temp/probe header | 1 = 3V3, 3 = SDA, 4 = SCL |
| **P6** FAN | Cooling fan (5 V, tach) | 1 = 5V_FAN ⚡, 2 = FAN_RET, 4 = TACH |
| **P8** PANEL_LED | Panel status LED | 1 = LED_A, 2 = LED_K |
| **P10** RESET-EXT | External reset button | 1 = NRST, 2 = GND |
| **P11** CUTOFF-SW | Power cutoff switch (SYS→MAIN 5 V) | 1 = MAIN5V ⚡, 2 = SYS5V ⚡ |
| **P12** NTC-HOTSPOT | Cabinet hotspot NTC | 1 = NTC_TEMP, 2 = GND |
| **P13** MODO-B-UPLINK | Modo-B uplink to 4G | 1 = USART1_RX, 2 = DIN_4G, 3 = GND |

---

## Action items before the JLCPCB order

1. **Add LCSC part numbers** to the BOM (`fab-jlcpcb/…-BOM.csv`) — it exports value +
   footprint only; JLC PCBA matches on LCSC part #. Watch the odd ones:
   **LTC4040EUFD, SHT40-AD1B, TMP102, MP1584EN, AO4406A, Bourns SRU8028** — verify JLC/LCSC stock.
2. **Decide THT assembly** — JLC charges extra for through-hole (K1, SW1, C3/C10/C43,
   all connectors/sockets). Common approach: JLC does SMD, you hand-solder the
   connectors + sockets (also avoids paying JLC for the big Phoenix/JST parts).
3. **Resolve the P3 / P13 / H3 DNP question** above.
4. Do **not** BOM the three plug-in modules (bucket B).