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HW_ERR Warning

Antminer S19 – High Hardware Error Rate

High Hardware Error Rate — invalid nonces exceed the 1.5% healthy threshold; often escalates to 3-8% without intervention.

Warning — Should be addressed soon

Affected Models: Antminer S19, S19 Pro, S19j, S19j Pro, S19 XP, S19 XP Hydro, S19k Pro

Quick answer

High Hardware Error Rate — invalid nonces exceed the 1.5% healthy threshold; often escalates to 3-8% without intervention. First step: Hard power-cycle the miner for 30 seconds at the breaker, then power back up.

Symptoms

  • Dashboard HW% above 2% sustained for 30+ minutes
  • Realized hashrate 5-15% below nameplate despite healthy UI
  • `kern.log` / cgminer shows repeated `HW error` or `nonce error chain X` lines
  • One hashboard's HW% clearly worse than the other two
  • Rejected or stale shares climbing on pool side
  • Per-chain temperature drifting up 3-5 °C vs baseline
  • PSU fan ramping during steady-state mining
  • High-frequency tick from hashboards during aggressive voltage scaling
  • On Braiins OS+/LuxOS/Vnish: one or more chip positions flagged red or >20% HW%
  • HW% pattern: sudden after profile change (OC/UV), or gradual over weeks (aging/thermal/caps)

Step-by-Step Fix

1

Hard power-cycle the miner for 30 seconds at the breaker, then power back up. Clears any wedged driver state from firmware updates.

2

Revert to stock (no OC, no UV) profile. Observe HW% for 15 minutes. If it drops below 1.5%, your tuning was the cause — rebuild the OC slower in Tier 2.

3

Shop-vac the intake filter; wipe the intake grille; verify no furniture, curtains, or dust buildup within 15 cm of the front of the miner. Dust = higher inlet temp = higher HW%.

4

Verify intake air temperature with an IR thermometer at the front grille — not room-middle. Target ≤ 35 °C standard, ≤ 40 °C Hydro.

5

Check Bitmain firmware version at support.bitmain.com/downloads. If you are on a known-buggy build for your hardware revision, roll one version back or forward.

6

Multimeter on DC, probe at the PSU-to-board connector while the miner is fully hashing. Expect ≥ 13.8 V sustained on a standard S19. Below = PSU tired or circuit undersized; swap PSU with a known-good unit.

7

Power off at the breaker. Re-seat every hashboard data and power cable; inspect for corrosion, blackening, or bent pins before reconnecting. Listen for the click.

8

Label the 3 hashboard slots 0/1/2 with tape. Swap the suspect board to a known-good slot. Observe HW%. If the fault follows the board = bad board; if it stays in the slot = bad control path.

9

Rebuild OC from stock: +100 MHz per step, 10-minute stability window between steps, stop at the last step before HW% crosses 2%. That is this miner's silicon-lottery ceiling — it varies per chip.

10

Measure line voltage at the panel under load. 235-245 V expected on 240 V split-phase; 202-212 V on 208 V commercial. Low line voltage drives PSU sag and elevated HW%.

11

Read per-chip HW% and record the worst positions after a 20-minute stabilisation — the single most valuable diagnostic step on an S19-class miner. Braiins OS+, LuxOS and Vnish publish install packages that expose per-chip HW% via their dashboards; check your exact model on each vendor's own list. DCENT_OS shows the same, but of the models on this page it publishes a downloadable signed experimental artifact only for the S19j Pro on a Zynq/Xilinx control board; the S19 and S19 Pro are named in the project with no public artifact, and the S19j, S19 XP, S19 XP Hydro and S19k Pro have no public DCENT_OS artifact and no install route. No model, S9 included, has a published witnessed install route yet — treat a DCENT_OS flash as a bench exercise on a spare unit, not a step on a producing miner. Status: https://d-central.tech/dcent-os/beta-status/.

12

Reflow the worst-performing chip: remove heatsink, flux the BGA, preheat bottom side to ~150 °C, top-side hot air at 310-330 °C for ~30 seconds. Let it cool naturally, re-apply thermal paste, reassemble. BM1398/1362/1368 tolerate a reflow cycle well.

13

Replace thermal paste on all chips with Arctic MX-6 or Thermal Grizzly Kryonaut. Uniform thin layer. Pay attention to PCH and voltage-domain ICs — dried pads there are a common drift cause.

14

Visually inspect capacitors and MLCCs around the voltage domain. Bulging electrolytics or cracked MLCCs near the PMIC need replacement. This is a soldering-iron + hot-air job, not a reflow job.

15

Roll firmware to the last-known-good version for your specific hardware revision. Verify the hardware table before flashing — wrong firmware for a late-rev board bricks the control board.

16

Stop DIY: per-chip HW% isolates the same chip position on two different boards, or a PMIC/voltage-domain IC is suspected. You are now in test-fixture territory — book a D-Central ASIC Repair slot.

17

D-Central bench process: test fixture with programmable load, per-chip isolation with official Bitmain test binaries, chip replacement with graded BM1398/1362/1368, reflow + reseal, 24-hour nameplate burn-in.

18

Ship hashboards in anti-static bags, double-boxed with ≥5 cm foam on every side. Include a note with observed symptoms, firmware version, and contact info — saves diagnostic time and your repair cost.

Know your exact variant: S19-family fixes differ by sub-model and board revision. The Antminer S19 family hub decodes every variant, chip, and spec so you match the right procedure to the unit on your bench.

When to Seek Professional Repair

Book a D-Central repair when: (a) per-chip HW% isolates the same chip position on two different hashboards, (b) PMIC/voltage-domain damage is suspected, (c) a second reflow on the same chip fails within 30 days, or (d) you see capacitor bulging or burnt-component odor.

Frequently Asked Questions

What does the HW_ERR error mean?

High Hardware Error Rate — invalid nonces exceed the 1.5% healthy threshold; often escalates to 3-8% without intervention. Commonly reported on: Antminer S19, S19 Pro, S19j, S19j Pro, S19 XP, S19 XP Hydro, S19k Pro.

Can I fix the HW_ERR error myself?

This is a moderate repair that needs some hands-on ASIC experience and the right tools. Start with: Hard power-cycle the miner for 30 seconds at the breaker, then power back up. Clears any wedged driver state from firmware updates. If you are not equipped for board-level work, D-Central can diagnose and repair it at our Montreal bench.

How much does it cost to repair?

Many cases are a free or low-cost DIY fix; a full bench repair runs up to $900 CAD. D-Central can diagnose and quote it.

Key Terms in This Fault

Jump to the full definition of the technical terms involved in this fault:

Related Error Codes

Decode this on your own terms — DCENT_OS

DCENT_OS is D-Central’s open-source, GPL-3.0 firmware effort for Antminer hardware — publishing guarded experimental artifacts for exact S9 XIL and S19j Pro XIL lanes; their install evidence remains incomplete. It is experimental and not production-ready, and it can brick a miner if you flash without a recovery path. We build on the shoulders of the open-firmware projects that came before us. Leave your email for build announcements from the firmware that surfaces and decodes faults like this one. This is a free public beta, never a pre-order — collection only, we will not email you anything else yet.

Printable quick-reference cards

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