ASIC Troubleshooting Database

S21 error-code decision table

Use S21-family error codes as a routing tool before replacing parts. The same visible warning can come from power, thermal, network, firmware, or board-level causes, so preserve logs and change one variable at a time.

Error signal	Likely class	First safe check	Repair decision
R:1, high temp, thermal shutdown	Thermal protection	Stop the miner, check ambient temperature, dust, fan speed, airflow direction, and heatsink contact before another full-power run.	Escalate if the fault returns after cleaning, fan validation, and safe ambient conditions; repeated thermal trips can damage hashboards.
Find 0 ASIC, find fewer than expected chips, missing chain	Hashboard or signal path	Save the kernel log, reseat or replace the data cable, confirm PSU stability, and note whether the fault follows a specific board.	Use bench diagnosis when chip count stays low or a board disappears repeatedly; avoid blind chip replacement.
Fan lost, fan speed abnormal, fan check fail	Cooling control	Inspect fan connectors, fan orientation, blocked blades, failed bearings, and control-board fan headers.	Replace failed fans first; escalate if known-good fans are not detected or fan control remains unstable.
Power voltage abnormal, PSU protection, power lost	Power delivery	Verify the circuit, PDU, cable, input voltage, PSU model, and load stability before blaming the hashboard.	Bench-test the PSU and boards if voltage errors persist, connectors show heat damage, or the unit trips breakers.
Pool, DNS, network, socket, rejected shares	Configuration or network	Check worker name, wallet/pool URL, DNS, gateway, switch port, firmware time sync, and pool-side accepted hashrate.	Repair is usually unnecessary unless network faults persist across known-good cables, firmware, and control-board tests.
Boot loop, firmware upgrade failure, no web UI	Firmware or control board	Try documented recovery with the correct firmware for the exact S21-family model and preserve logs before flashing.	Escalate if recovery fails, storage is corrupted, or the control board cannot reliably communicate with hashboards.

If a warning involves burned smell, melted connectors, corrosion, liquid exposure, repeated missing hashboards, or breaker trips, stop power-cycling and use repair intake.

650+ error codes with step-by-step fixes for every major ASIC miner.

Manufacturer

Severity

DIY Difficulty

12 loaded

Most Common Issues

Antminer S19 – Temperature Too High (Temp1/Temp2 > 95°C)

Antminer S19, S19 Pro, S19j Pro, S19 XP, S19k Pro (3250 W...

Antminer S19 – Hashboard Not Detected (0 ASIC)

Antminer S19, S19 Pro, S19j Pro, S19 XP, S19k Pro

Antminer S9 – Fan Speed Error

Antminer S9, S9i, S9j, S9k, S9 SE

Whatsminer M30S – Power Supply Failure

Whatsminer M30S, M30S+, M30S++

Error Code Library

Showing 12 curated troubleshooting entries on page 1 of the paginated library.

12V Rail Sag — Hashboard Brownout Under Load

Cross-cutting: every external-PSU ASIC miner — Antminer S9 / S17 / S19...

Antminer – 220V to 110V Wrong Connection

Antminer S9, S9i, S9j, S9k, S9 SE, S17, S17 Pro, S17+, S19,...

Antminer – APW PSU Fan Failure

Antminer APW3++, APW7, APW9, APW9+, APW12 (the full Bitmain APW power supply...

Antminer – APW PSU Not Powering On

APW3++, APW7, APW9, APW9+, APW12 — across Antminer S9, S9i, S9j, S9k,...

Antminer – Autotune Firmware Crash

Antminer S17 · S17 Pro · S17+ · S17e · S19 ·...

Antminer – BHB42 BMMiner Version Mismatch

Antminer units reporting model string ANTMINER BHB42xxx — predominantly S17 / S17...

Antminer – CGMiner / BMMiner Crash

Antminer S9 · S9i · S9j · T9+ · L3+ · L7...

Antminer – Control Board Beeping

All Antminers with on-board buzzer: S9, S9j, S9k, S17, S17 Pro, S17+,...

Antminer – Control Board Clock Drift

Antminer S9, S17, S17 Pro, S19, S19 Pro, S19j, S19j Pro, S19...

Antminer – Control Board Ethernet Port Failure

Antminer S9, T9, R4, L3+, T17, S17, S17+, S17 Pro, T19, S19,...

Antminer – Custom Firmware Bricked Control Board

Antminer S9 · S9j · S9k · T9+ · S17 · S17...

Antminer – Factory Reset Procedure

S9 · S9i · S9j · S9k · T17 · S17 ·...

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Editorial review and limitations

Reviewed by D-Central's mining hardware and ASIC repair editorial team for practical accuracy, buyer risk, repair context, and operational assumptions. Verify current hardware price, stock, network difficulty, BTC price, power rate, shipping, tax, firmware, and device condition before buying, hosting, repairing, or retiring mining hardware.

Last reviewed May 24, 2026. D-Central, Laval, Quebec.

Related products, repair, and setup paths

Last reviewed May 25, 2026. Added to route educational and product traffic toward exact commercial next steps.