This is shared Antminer S19 Series reference material covering 5 models. Components, supply voltage/phase, PSU, cooling and service procedures vary by model and revision. Use the exact model nameplate and OEM manual; shared examples do not establish compatibility.
Every unit is built from the same handful of parts. Learn what each does, how to identify it, and - most importantly for diagnosis - what its failure looks like.
A small Linux single-board computer - the miner's brain. It fetches work from the pool over Ethernet, splits and streams it to the three hashboards, collects nonces back, monitors temps/fans, and serves the web UI. S19 uses a Xilinx Zynq SoC (dual ARM Cortex-A9 + FPGA hardware-UART); S21 moved to an Amlogic board with software-UART and I²C/DAC voltage control.
Networking, configuration, monitoring, and work dispatch. No CB = no miner.
The only board with an RJ45 Ethernet jack, microSD slot, reset button, IP-report button, two LEDs, and three ribbon sockets to the hashboards. Field part numbers: Ctrl_C87 / Ctrl_C55 / Ctrl_C52 (Zynq).
One of THREE identical PCBs (Chain 0/1/2) packed with ASIC chips that do the actual SHA-256 hashing. Each is an independent daisy-chain of chips grouped into series voltage domains, with its own signal ribbon (to the CB) and heavy DC power cables (to the PSU).
Does 100% of the hashing. Three boards ≈ full rated hashrate; lose one and you lose ~1/3.
The three long finned boards stacked in the chassis. Each carries a silkscreen PCB number (e.g. BHB42831, BHB56801, BHB68603) that identifies the exact revision - critical for ordering a replacement.
Purpose-built SHA-256 engines soldered in rows down each hashboard. Job data enters chip 1 → 2 → 3 … in a daisy chain; each chip grinds billions of nonce guesses and passes hits back. Efficiency (J/TH) is set by the chip generation.
The fundamental hashing unit - where the TH/s comes from.
Small black squares hidden under the heatsinks (don't remove them in the field). Chip-to-model map: BM1398 → S19/S19 Pro/T19 · BM1362 → S19j/S19j Pro(+) · BM1366 → S19 XP/S19k Pro · BM1368 → S21/T21 · BM1370 → S21 Pro/XP.
Voltage domains group the ASIC power distribution. Power topology and serial chip communications are different circuits; exact wiring and fault propagation require a revision-specific schematic. The prior series-chip assertion is unverified and must not guide a repair.
How the board delivers usable voltage to many chips efficiently. Voltage is regulated per DOMAIN, not per chip.
Visually repeating blocks of chips along the board; silkscreen chip numbers (BM01…BMn) run along the chain. Per-domain voltages appear on the dashboard.
On S17/S19, a small 8-bit gatekeeper chip on EACH hashboard (PIC16F1704-class). It switches the on-board DC-DC converters on, holds a heartbeat/watchdog, and provides the enable/handshake that makes the control board trust the board.
Power-enable + handshake for the hashboard. Without its 'OK', the board won't come up.
Small SOIC/TSSOP microcontroller near the hashboard's power-enable circuitry.
A tiny I²C memory chip on each hashboard (AT24C02-class) storing the board's identity and calibration: serial number, chip bin/frequency profiles, voltage settings, board revision. The control board reads it to know how to drive that board.
Tells the CB how to configure and tune that specific hashboard.
Small 8-pin chip on the hashboard's I²C bus (address 0x50).
I²C sensors (TMP75-class), typically two per hashboard at the hot zones, reporting inlet/chip temperature to the firmware. The firmware uses them to set fan speed and to trigger thermal protection.
The cooling feedback loop and the trigger for over-temp shutdown.
Small sensor chips on each hashboard; reported per board on the status page (e.g. 'Temp 62 / 75 °C').
Short flat ribbon cables carrying serial data (job out, nonce back), the ~25 MHz clock, reset, and the I²C lines (EEPROM + temp sensors) between the control board and each hashboard.
The nervous system between CB and hashboards. THE most common innocent cause of scary errors.
Flat multicore ribbons with keyed plastic connectors at each end, CB → hashboard header.
Aluminum fins clipped to each ASIC (with non-conductive thermal pad/paste beneath) that pull heat off the dies into the airstream. On S19 these are individual blocks; some boards use larger finned assemblies.
Move heat from chip to air so the board stays in a safe thermal window.
The metal fins you see looking into the board stack.
The PSU converts its specified AC input to board DC. APW12 is an S19 air-model example; verify exact miner/PSU revision, voltage, phase and current requirements. S21 air and liquid PSU assignments differ; family names do not establish compatibility.
Feeds all three hashboards and the control board. A weak PSU often shows as an intermittent board, not a fully dead unit.
Module with the AC inlet outside and DC output cables to the boards. APW12 suffix = output window (APW121215 = 12-15 V). 'C19/C20' refers to the fat AC cord/inlet, not a PSU model.
Four 12 V high-static-pressure fans (2 intake front, 2 exhaust rear), 120×120×38 mm, up to ~2.7 A, ~6,000 RPM (some 7,200). The control board reads each fan's TACHOMETER and throttles/alarms on low RPM.
Force air through the heatsink tunnel. The miner throttles or refuses to run without them (safety).
Large fans bolted to the front/rear grilles. Connector: 6-pin on classic S19/Pro/j Pro; 4-pin square on S19k Pro / S21 / T21 (adapters exist).