What This Error Means

The “Voltage Error” — also displayed as “Voltage too low,” “Voltage out of range,” “Power domain error,” or “VDD error” — means the miner has detected that the voltage being supplied to one or more hashboard power domains is outside the acceptable operating range. ASIC chips require precisely regulated voltage to operate correctly. When voltage drops below the minimum threshold or exceeds the maximum, the firmware flags the error and may shut down the affected chain to prevent damage.

On modern Antminer models (S17 and later), each hashboard is divided into multiple voltage domains, each regulated by its own DC-DC converter. A failure in any single voltage domain affects only the chips in that domain, but the control board may take the entire chain offline for safety. On older models like the S9, simpler voltage regulation means issues tend to affect the entire board.

Common Causes

Failing voltage regulator (VRM/DC-DC converter) — The voltage regulator module on the hashboard has degraded or failed, outputting incorrect voltage to its chip domain. This is the most common hardware cause.
PSU output degradation — The power supply unit is not delivering stable input voltage to the hashboard, causing the on-board regulators to fall out of range. A PSU nearing end-of-life often shows voltage instability under load.
Damaged power cable or connector — High-resistance connections (corroded pins, melted connectors, loose cables) cause voltage drop between the PSU and hashboard, especially under full mining load.
Short circuit on the hashboard — A failed component (chip, capacitor, or trace) on the hashboard creates a partial short that pulls down the voltage in its domain.
Incorrect firmware voltage settings — Custom firmware or overclocking settings have configured a voltage outside the safe operating range for the installed hardware.
Input power instability — The wall power feeding the PSU is fluctuating due to grid instability, undersized wiring, or sharing a circuit with high-draw appliances.

Step-by-Step Fix

Safety first: Voltage issues can indicate dangerous conditions including short circuits and overheating connectors. Power off and disconnect the miner before any physical inspection. Check for burning smells, melted plastic, or discoloration before proceeding.

Step 1: Document the Error

Log into the miner web interface and note the exact error message, which chain is affected, and any voltage readings displayed. Some firmware versions show the actual voltage reading alongside the error. Document these values — they help determine whether the voltage is too low, too high, or fluctuating.

Step 2: Check for Physical Damage

Power off and open the miner. Visually inspect all power connectors for melting, discoloration, or burn marks. Examine the hashboard surface for any discolored components, swollen capacitors, or areas that appear darker than surrounding components. Smell for any burnt electronics odor. If you find physical damage, do not attempt to power on — send for professional repair.

Step 3: Inspect and Reseat Power Cables

Disconnect all power cables between the PSU and hashboards. Inspect each connector — the pins should be straight, clean, and show no signs of heat damage. Firmly reseat all connections. If you have spare power cables, try replacing the cables to the affected chain.

Step 4: Test PSU Output

With a multimeter, check the PSU output voltage at the connector. With the miner running (carefully measuring at an accessible point), the voltage should be stable and within specification. Voltage that fluctuates by more than 0.5V under load or that sags significantly from its no-load reading indicates a failing PSU.

Step 5: Isolate the Affected Hashboard

Disconnect the affected hashboard’s power and data cables. Power on the miner with only the remaining two hashboards connected. If the miner runs normally on two boards, the disconnected hashboard or its power path is the problem. If voltage errors appear on other chains too, the issue may be the PSU or the control board.

Step 6: Reset to Default Firmware Settings

If you have applied any custom voltage settings, overclocking profiles, or third-party firmware, revert to stock Bitmain firmware and default settings. This eliminates software-configured voltage issues. Perform an SD card recovery flash for a complete reset.

Step 7: Check Input Power Quality

Measure the wall voltage at the outlet while the miner is running. If voltage drops below 210V (for a 240V circuit) or fluctuates significantly, you may need a dedicated circuit, thicker wiring, or to move the miner to a more stable power source. An inline power meter can help monitor voltage stability over time.

Advanced Diagnosis

Via SSH for voltage-specific diagnostics:

ssh root@[miner-ip]
cat /var/log/messages | grep -i "volt"
cat /var/log/messages | grep -i "power"
cat /var/log/messages | grep -i "domain"
# Look for specific voltage domain failures and readings

Voltage domain mapping: On S19-series boards, each voltage domain powers a group of 3-4 chips. If the error references a specific domain number, this maps to a specific physical section of the hashboard. Knowing which domain failed helps the repair technician locate the faulty regulator without probing every component.

Oscilloscope testing: For intermittent voltage errors, a multimeter may not capture the fault. An oscilloscope connected to the voltage domain output can reveal transient voltage spikes, dropout events, or excessive ripple that a multimeter averages out. This is professional-level diagnostics.

When to Get Professional Help

Seek professional ASIC repair if:

You see physical damage on connectors, the hashboard, or the PSU
The voltage error persists after cable replacement and PSU verification — indicates a hashboard-level voltage regulator failure
Multiple voltage domains on a single board are failing — board-level component repair required
The error appears immediately on boot before the miner reaches full load — likely a short circuit or dead regulator

D-Central Technologies performs voltage regulator diagnostics and replacement on all Antminer hashboards. We test every voltage domain, identify failed regulators and associated components, and perform board-level repair to restore proper power delivery. Submit a repair request here

Affected Models

Voltage errors affect all Antminer models but are particularly common on: S17 and T17 (voltage regulator reliability issues), S19 series (multiple voltage domains per board increase the number of potential failure points), and any miner that has experienced a power surge. The S9’s simpler voltage regulation means fewer domain-specific failures but more catastrophic failures when they occur.

Related Error Codes

Power Supply Failure / PSU Not Detected — PSU issues can cause or mimic voltage errors
Chain X Only / Missing Hashboard — Voltage failures prevent chain initialization
ASIC Chip Error / Dead ASIC — Chip failures can cause voltage domain shorts
Low Hashrate — Marginal voltage causes reduced chip performance before triggering errors
EEPROM Error — Voltage spikes during EEPROM writes corrupt data

Frequently Asked Questions

Can voltage errors damage my miner permanently?

Over-voltage can permanently damage ASIC chips by exceeding their rated voltage tolerance. Under-voltage typically does not cause permanent damage but prevents proper operation. If the voltage error is caused by a short circuit on the hashboard, continuing to operate could worsen the damage. Always investigate and resolve voltage errors promptly rather than ignoring them.

Is it safe to run my miner if only one chain has a voltage error?

You can operate the miner with the affected chain disconnected (remove its power and data cables) while running the remaining two chains. Do not leave the affected hashboard connected and powered while it has voltage errors — this can stress the PSU and potentially cause secondary damage. Disconnect it until repaired.

Can a bad power cable really cause voltage errors?

Yes, absolutely. A power cable with high resistance (from corrosion, melted contacts, or internal wire damage) causes a voltage drop that increases under load. At idle or low power, the voltage may appear fine, but when all chips on a hashboard are hashing at full power and drawing maximum current, the voltage drop across a bad cable can be significant enough to trigger the error. Always use high-quality cables rated for the current they carry.

What causes voltage regulators to fail?

Voltage regulators on hashboards fail due to: thermal stress from operating near their current limits, power surges, capacitor aging (electrolytic capacitors dry out over time), and manufacturing quality variations. Maintaining good cooling and clean power significantly extends voltage regulator life. Regulators in well-cooled miners running at stock settings can last 5+ years; overclocked miners in hot environments may see failures in 1-2 years.

Voltage Error Fix — Antminer Voltage Too Low Troubleshooting Guide