Whatsminer M30S/M30S+ Maintenance & Repair Guide: Complete Diagnostic Manual

Introduction

The MicroBT Whatsminer M30S is the machine that earned MicroBT its seat at the table alongside Bitmain. Released in early 2020, the M30S delivered 86 TH/s of SHA-256 hashrate at 38 J/TH — and then MicroBT kept pushing. The M30S+ hit 100 TH/s, and the M30S++ pushed to 112 TH/s. Within a single product generation, MicroBT carved out a massive share of the global hashrate and proved that Bitmain’s monopoly on high-performance SHA-256 miners was over.

What makes the M30S lineage fundamentally different from anything Bitmain builds is its integrated architecture. The power supply is built directly into the chassis — not a separate box connected by heavy cables like every Antminer you have ever touched. This is not a minor design choice. It changes how you power the machine, how you diagnose faults, and how you approach every repair. If you are an experienced Antminer technician picking up a Whatsminer for the first time, forget half of what you know. The M30S plays by different rules.

At the heart of the M30S sits a custom MicroBT ASIC chip fabricated on Samsung’s 8nm process. These are not Bitmain BM-series chips — MicroBT designs their own silicon from the ground up. Three hashboards, each populated with these custom ASICs, connect to a control board running WhatsMinerOS, a Linux-based firmware with its own web interface, its own API, and its own set of error codes. If you have spent years navigating Antminer dashboards, the WhatsMiner interface will feel foreign. Good. It means you are learning something new.

The M30S series became the workhorse of mid-scale mining operations and a favorite among home miners who appreciated the cleaner industrial design and the built-in PSU that eliminated the rat’s nest of power cables that defines an Antminer installation. Hundreds of thousands of these machines are deployed worldwide, and they need maintenance, diagnostics, and repairs just like any other high-performance computing hardware running 24/7 in demanding environments.

This guide is D-Central’s first comprehensive Whatsminer manual — and we are building it the same way we build everything: thorough, practical, and written by technicians who have actually done the work. We cover the full lifecycle: initial setup, preventive maintenance, diagnostics, common repairs, firmware management, and the decision tree for when to fix it yourself versus when to ship it to a professional.

Model Variants Reference

The M30S series spans three performance tiers built on the same platform. Understanding which variant you are working on matters for diagnostics — expected hashrate, power draw, and chip counts differ between models, and knowing the baseline is essential for spotting abnormal behavior.

The progression from M30S to M30S++ is primarily a chip binning story. MicroBT manufactures the same ASIC wafer and then sorts chips by quality. The best-performing chips — those that achieve higher clock speeds at lower voltage — go into the M30S++. The mid-tier go into the M30S+. The standard bin goes into the M30S. Same silicon, different selection criteria. This means the physical hardware is nearly identical across all three variants, but the firmware is configured with different frequency and voltage profiles to match the chip quality.

M30S vs. Antminer S19 — Platform Comparison

If you are coming from the Antminer world, understanding the architectural differences between the M30S and the S19 is critical. These are not minor variations — they are fundamentally different engineering philosophies.

Hardware Architecture

Understanding the M30S hardware layout before you open the case is the difference between efficient diagnosis and fumbling around with a flashlight. The M30S is a more tightly integrated machine than an Antminer — everything is packed into a single enclosure, and the component arrangement reflects MicroBT’s engineering philosophy of minimizing external connections.

Control Board

The M30S control board runs WhatsMinerOS, a Linux-based operating system developed by MicroBT. Unlike Antminer’s CGMiner-based firmware, WhatsMinerOS uses MicroBT’s proprietary mining software and management interface. The control board handles pool communication, hashboard orchestration, temperature monitoring, and fan speed regulation.

Key control board details:

• Processor: ARM-based SoC running embedded Linux
• Network: Single Ethernet port (RJ45, 10/100 Mbps) — no WiFi capability
• Status LEDs: Green (normal), Red (fault), and network activity indicators
• Reset button: Recessed pinhole button for factory reset (hold for 10+ seconds)
• API access: btminerapi service on port 4028 (similar to CGMiner API but with MicroBT-specific commands)
• SD card slot: Used for firmware recovery and updates

Hashboards

The M30S contains 3 hashboards, each populated with MicroBT’s custom ASIC chips fabricated on Samsung’s 8nm process. Each hashboard connects to the control board and the integrated PSU through 4-pin connectors — a notable difference from Antminer’s separate ribbon cables and power connectors.

Hashboard characteristics:

• ASIC chips: MicroBT custom design, Samsung 8nm fabrication — NOT Bitmain BM-series
• Chips per board: Varies by batch (typically 66–117 chips depending on variant and revision)
• Packaging: BGA (Ball Grid Array) — requires hot-air rework station for chip replacement
• Connectors: 4-pin integrated connectors carrying both power and data signals
• Temperature sensors: Multiple on-board sensors reported through WhatsMinerOS
• LED indicators: Each hashboard has status LEDs visible through chassis ventilation slots

The hashboard layout is physically different from Antminer boards. Whatsminer hashboards are slightly wider, the heatsink mounting system uses a different pattern, and the ASIC chip pitch is different. Antminer hashboard repair experience transfers conceptually (voltage domain testing, signal tracing, BGA rework), but the specific procedures, test points, and component locations are all Whatsminer-specific.

Integrated Power Supply

This is where the M30S diverges most dramatically from the Antminer platform. The power supply is built into the miner chassis — it is not a separate APW box. AC mains power enters the unit through a C19/C20 inlet on the rear panel. The internal PSU converts AC to the DC voltage rails required by the hashboards and control board.

PSU specifications:

• Input voltage: 200–277V AC (wider range than Antminer’s 200–240V)
• Input frequency: 50/60 Hz
• Output: Multiple DC voltage rails supplying hashboards and control board
• Power factor correction: Active PFC
• Protection: Over-current, over-voltage, short-circuit, and over-temperature protection
• Efficiency: 93%+ at full load

Fan System

The M30S uses 2 large fans — one intake, one exhaust — controlled dynamically by the firmware based on chip temperature readings. This is different from Antminer’s typical 4-fan configuration (2 intake + 2 exhaust). The Whatsminer fans are physically larger than Antminer fans, moving more air per fan but with different acoustic characteristics.

Fan details:

• Count: 2 (one intake fan at front, one exhaust fan at rear)
• Size: Large-diameter (larger than Antminer’s fans)
• Control: PWM speed control via firmware — speed adjusts automatically based on chip temperature
• Connectors: 4-pin fan connectors (power + PWM + tachometer)
• Error codes: Fan failures generate specific error codes (F1 for front fan, F2 for rear fan)
• Airflow direction: Front-to-rear (air enters front panel, passes over hashboards, exits rear panel)

The dual-fan design means a single fan failure has a larger impact on cooling than losing one of four fans on an Antminer. If either fan fails on an M30S, the unit will typically trigger a thermal protection shutdown much faster than an Antminer losing one of its four fans. Fan maintenance is therefore more critical on Whatsminer hardware.

Network Connectivity

The M30S connects to your network via a single Ethernet RJ45 port on the control board. There is no WiFi capability — this is a wired-only device. The control board supports DHCP (automatic IP assignment) by default, and the IP address can be set to static through the web interface after initial connection.

Technical Specifications

Before You Begin

Safety Warnings

Initial Setup & Configuration

Physical Setup

Getting the physical installation right is the single most important thing you can do for the long-term health of your M30S. More miners die from poor environmental conditions than from manufacturing defects.

1. Location selection: Choose a well-ventilated area with ambient temperature below 35°C. The M30S exhausts significant heat — do not place it in an enclosed space without exhaust ventilation. Basements, utility rooms, and dedicated mining closets with ducting are ideal. Garages work in Canada’s winter but become thermal nightmares in summer.
2. Surface: Place the miner on a flat, stable, non-conductive surface. A wire rack or metal shelf works well and allows airflow beneath the unit. Never place on carpet or soft surfaces that can block bottom ventilation.
3. Airflow clearance: Maintain at least 15 cm of clearance at the front intake and 30 cm at the rear exhaust. Do not place M30S units face-to-face — one unit’s exhaust becomes the other’s intake, causing thermal stacking.
4. Power connection: Use a C19/C20 power cord rated for your miner’s wattage. The M30S does NOT use the smaller C13/C14 connector that Antminers use via their APW PSU. Ensure the outlet is on a dedicated 220–277V AC circuit. In North American homes, this is the same type of circuit used for electric dryers or EV chargers. Consult a licensed electrician if you do not have an appropriate circuit available.
5. Ethernet: Connect a Cat5e or better Ethernet cable from the M30S control board to your network switch or router. WiFi is not an option — the M30S is wired-only.

Network Connection & IP Discovery

Once the M30S is powered on and connected via Ethernet, you need to find its IP address to access the management interface.

1. DHCP (default): The M30S requests an IP address from your router via DHCP by default. Check your router’s admin page for a new device appearing on the network. It will typically show up as “WhatsMiner” or with a MAC address prefix starting with C4:11:04 or similar MicroBT OUI.
2. Network scanner: If you cannot access your router’s DHCP client list, use a network scanner like Angry IP Scanner, Advanced IP Scanner (Windows), or nmap on the command line. Scan your local subnet for devices with port 80 open.
3. WhatsMiner Tool: MicroBT provides an official WhatsMinerTool utility for Windows that can discover Whatsminer devices on your local network, configure pool settings in bulk, and update firmware. Download it from MicroBT’s official support channels.

# Linux/macOS — scan for devices with port 80 open on your subnet
nmap -sn 192.168.1.0/24 --open -p 80

# Or use the WhatsMiner API port for more precise detection
nmap -p 4028 192.168.1.0/24 --open

Web Interface Walkthrough

Once you have the IP address, open a web browser and navigate to http://<miner-ip>. The WhatsMinerOS web interface is different from what Antminer users expect — here is what you will see:

1. Login: Default credentials are typically admin / admin. Some units ship with the password printed on a label on the control board or packaging. Change the password immediately after first login.
2. Dashboard: The main page displays real-time hashrate, chip temperature, fan speed, pool status, and uptime. Unlike Antminer’s dashboard that shows individual chain/board statistics, WhatsMinerOS aggregates some metrics differently. Look for all 3 hashboards reporting normal chip counts.
3. Miner Configuration: This is where you set your mining pool URLs, worker names, and passwords. The M30S supports up to 3 pool configurations (primary, secondary, tertiary failover).
4. System: Network settings (DHCP or static IP), timezone, hostname, and firmware version information.
5. Logs: System logs and error history — critical for diagnostics.

Pool Configuration

Navigate to the Miner Configuration page and enter your pool details:

• Pool 1 (Primary): Your main mining pool URL (e.g., stratum+tcp://pool.example.com:3333)
• Worker: Your worker name (typically wallet_address.worker_name or username.worker_name depending on the pool)
• Password: Usually x or your pool’s specified password
• Pool 2 & 3: Configure backup pools for failover. If Pool 1 goes down, the miner automatically switches to Pool 2, then Pool 3

After entering pool details, click Save & Apply. The miner will restart its mining process and begin hashing against your configured pool. Allow 5–10 minutes for the hashrate to stabilize — initial ramp-up is normal.

Setting Up Monitoring & Alerts

The WhatsMinerOS web interface provides basic monitoring, but for serious operations you want external monitoring. Key approaches:

• Pool-side monitoring: Most pools provide worker dashboards showing hashrate, accepted/rejected shares, and uptime. Set up email or Telegram alerts for workers going offline.
• WhatsMiner API: The btminerapi service on port 4028 accepts JSON-formatted commands. You can query status, temperature, fan speed, and error codes programmatically. Use this to build custom monitoring scripts or integrate with tools like Foreman, Awesome Miner, or Minerstat.
• SNMP: Some WhatsMinerOS versions support SNMP monitoring for integration with enterprise monitoring platforms.

# Query miner summary (hashrate, temperature, uptime)
echo '{"cmd":"summary"}' | nc MINER_IP 4028

# Query detailed device status
echo '{"cmd":"devdetails"}' | nc MINER_IP 4028

# Query error codes and log entries
echo '{"cmd":"get_error_code"}' | nc MINER_IP 4028

# Query pool configuration
echo '{"cmd":"pools"}' | nc MINER_IP 4028

Preventive Maintenance Schedule

The M30S is a reliable machine, but “reliable” does not mean “maintenance-free.” Every component in this miner is operating at near-maximum capacity 24 hours a day, 7 days a week. Fans wear bearings. Dust accumulates on heatsinks. Thermal paste degrades. The difference between a miner that runs for five years and one that dies after two is almost always maintenance — not luck.

Daily: Dashboard Monitoring

This takes 60 seconds. Open the web interface or check your monitoring dashboard. Verify:

• Hashrate: All 3 hashboards producing expected hashrate. Total should be within 5% of rated spec (M30S: ~86 TH/s, M30S+: ~100 TH/s, M30S++: ~112 TH/s)
• Chip temperatures: All readings between 50°C and 75°C. Any board consistently above 80°C needs investigation
• Fan speeds: Both fans reporting normal RPM. Sudden speed increases indicate thermal stress. Zero RPM on either fan means immediate shutdown required
• Accepted/rejected shares: Reject rate should be below 1%. Higher rejection rates suggest network issues, pool problems, or hardware instability
• Error codes: Check the system log for any new error codes. The WhatsMinerOS error format is different from Antminer — see the error codes section for details

Monthly: Fan Cleaning & Log Review

1. Power down the miner. Unplug the power cord. Wait 10 minutes.
2. External cleaning: Use compressed air to blow dust from the intake and exhaust grilles. Blast air through the ventilation slots from both sides.
3. Fan inspection: Look through the grilles for visible dust buildup on fan blades. Listen for any rattling or grinding when spinning the fans by hand (with power disconnected). If you hear bearing noise, schedule a fan replacement.
4. Error log review: Open the WhatsMinerOS web interface after powering back on. Review the system log for recurring error codes, temperature warnings, or hashboard disconnections over the past month. Patterns in the logs often predict failures before they become catastrophic.
5. Ethernet cable check: Verify the Ethernet cable is securely seated. A loose cable can cause intermittent network drops that look like pool problems but are actually local.

Quarterly: Deep Clean & Thermal Inspection

1. Power down, unplug, wait 10 minutes. Always.
2. Remove chassis cover (Phillips screws — note their locations, M30S uses different screw lengths in some positions).
3. Compressed air deep clean: Blow out all dust from hashboard heatsinks, between hashboards, around the PSU area, and from the control board. Use short bursts — sustained high-pressure air can spin fans past their rated speed and damage bearings. Hold fan blades still while blowing near them.
4. Visual inspection: Look for discoloration on hashboard PCBs (brown/yellow spots indicate overheating), swollen or leaking capacitors, corroded connectors, and cracked solder joints. Use a flashlight and magnifier.
5. Connector check: Verify all 4-pin hashboard connectors are firmly seated. MicroBT’s connectors can work loose over time due to thermal cycling. Push each connector firmly into its socket.
6. Thermal paste visual check: If any heatsinks appear to have uneven thermal contact (one corner hot, opposite corner cool), schedule a thermal paste replacement at the next maintenance window.
7. Fan blade cleaning: If dust is caked on fan blades (common in homes with pets or high-dust environments), carefully clean each blade with 99% IPA on a lint-free cloth.

Annually: Full Disassembly & Hashboard Inspection

1. Complete disassembly of all three hashboards from the chassis.
2. Thermal paste replacement: Remove heatsinks, clean old thermal paste with 99% IPA, apply fresh non-conductive thermal paste. This is the single highest-impact annual maintenance task. Degraded thermal paste increases chip temperatures by 10–20°C and reduces hashrate through thermal throttling.
3. Hashboard microscope inspection: Under magnification, check for cracked BGA solder joints, damaged traces, corroded pads, and components showing thermal stress (discoloration, swelling).
4. Fan replacement evaluation: After 18–24 months of continuous operation, most fans are approaching end of life even if they still spin. Proactive replacement at this interval prevents the scenario where a fan seizes during unattended operation and the miner overheats.
5. PSU inspection: With the chassis open, visually inspect the integrated PSU for swollen capacitors, burn marks, or damaged connectors. Listen for buzzing or clicking from the PSU area during a brief power-on test.
6. Control board inspection: Check the SD card slot for corrosion, verify the Ethernet port is undamaged, and confirm the reset button is functional.

Common Issues & Diagnostics

When a Whatsminer M30S stops performing, the diagnostic process is different from Antminer troubleshooting. Different error codes, different web interface, different signal architecture. This section covers the most common M30S failure modes and how to identify them.

Hashboard Not Detected

A missing hashboard is the most common M30S issue. The web interface shows only 2 of 3 hashboards, or one board shows 0 TH/s.

Diagnostic steps:

1. Check LED indicators: Each hashboard has status LEDs visible through the chassis. A non-blinking or red LED on a specific hashboard identifies it as the problem board.
2. Power cycle: Sometimes a simple power cycle resolves a hashboard detection failure caused by a firmware glitch. Power off, wait 30 seconds, power on. This fixes the problem roughly 15% of the time.
3. Reseat connectors: Power off and unplug. Open the chassis. Firmly reseat the 4-pin connector for the missing hashboard at both the hashboard end and the control board end. The M30S uses 4-pin connectors that carry both power and data — a partial seat on any pin can cause detection failure. This resolves the issue about 25–30% of the time.
4. Swap connectors: Swap the connector cables between a working hashboard and the non-working one. If the problem follows the cable, you have a bad cable. If the problem stays with the same board position, the issue is the hashboard itself or the control board port.
5. Cross-test hashboard: If possible, test the suspected bad hashboard in a known-good miner, or test a known-good hashboard in the suspect miner’s slot. This definitively isolates whether the fault is in the hashboard, the cable, or the control board.
6. Check PSU output: If no hashboards are detected, the integrated PSU may have failed. Measure DC output voltage at the hashboard power connector — you should see the expected voltage rail under load.

Low Hashrate

All 3 hashboards are detected, but total hashrate is significantly below spec — for example, an M30S showing 65 TH/s instead of the expected 86 TH/s.

Diagnostic steps:

1. Check individual board hashrates: If one board is producing significantly less than the other two, the problem is localized to that board. Dead ASIC chips within a voltage domain reduce that board’s contribution.
2. Check chip temperatures: If temperatures are above 80°C, the firmware is likely throttling frequency to prevent damage. This is a thermal problem, not a chip problem. Address cooling first (cleaning, thermal paste, ambient temperature, fan health).
3. Check for ASIC chip errors: The WhatsMinerOS log will report individual chip failures. A few dead chips across a board will reduce that board’s hashrate proportionally. Five or more dead chips on a single board typically means the board needs professional repair.
4. Check power supply stability: An underperforming PSU that cannot deliver full rated power will cause all three boards to hash below spec simultaneously. If all three boards show proportionally reduced hashrate, suspect the PSU.
5. Check pool latency: High network latency to your pool increases stale shares and reduces effective hashrate. This appears as low hashrate on the pool dashboard while the miner dashboard shows normal local hashrate. Check your reject rate — it should be below 1%.

Fan Errors (F1/F2)

The M30S generates specific error codes for fan failures. F1 typically indicates the front (intake) fan, and F2 indicates the rear (exhaust) fan. Because the M30S has only 2 fans (versus 4 on most Antminers), a single fan failure is more critical — it represents 50% of cooling capacity.

Diagnostic steps:

1. Listen: With the miner running (or during startup), listen for grinding, clicking, or rattling from either fan. Bearing wear produces distinctive sounds before complete failure.
2. Visual check: Look at both fans during operation. One should be visibly spinning at the front (intake) and one at the rear (exhaust). A stationary fan with the miner powered on is an immediate red flag.
3. RPM check: In the web interface, both fans should report RPM values. A fan reporting 0 RPM has failed. A fan reporting wildly fluctuating RPM has a failing bearing or loose connector.
4. Connector check: Power off and unplug. Check the 4-pin fan connector on the control board. Reseat it. A loose PWM or tachometer pin can cause phantom fan errors.
5. Swap test: If you have a spare fan, swap it into the failing position. If the error code clears, the original fan is dead and needs replacement.

PSU Issues

Because the PSU is integrated, PSU problems manifest differently than on an Antminer. There is no separate PSU to test independently — you are diagnosing it in-situ.

Symptoms of PSU failure:

• Miner does not power on at all (no fans, no LEDs, no network activity)
• Miner powers on briefly then shuts down (over-current or short-circuit protection tripping)
• All three hashboards underperforming equally (insufficient power delivery)
• Audible buzzing, clicking, or whining from the PSU area of the chassis
• Burning smell (stop immediately — this indicates component failure)

Diagnostic steps:

1. Verify AC input: Use a multimeter to confirm the wall outlet is delivering proper voltage (200–277V AC). A sagging circuit (shared with other heavy loads) can drop below the PSU’s minimum input, causing intermittent shutdowns.
2. Check the power cord: C19/C20 connectors can develop loose contacts. Try a different power cord if available. Damaged or undersized cords cause voltage drop under load.
3. Listen for relay clicks: When you plug in the M30S, you should hear internal relays engage. If the PSU is completely silent with power connected, the input stage may have failed.
4. Measure DC output: With the chassis open and the miner powered on (EXTREME CAUTION — lethal voltage present), measure the DC voltage at the hashboard power connectors. Compare against expected values for your model. Deviation of more than 5% from spec indicates PSU degradation.
5. Capacitor inspection: With the unit unplugged and discharged (10+ minutes), visually inspect PSU electrolytic capacitors for swelling, leaking, or bulging tops. Swollen capacitors are the most common PSU failure mode and are visually obvious.

Overheating & Thermal Protection

The M30S activates thermal protection when chip temperatures exceed approximately 85°C. The firmware will either throttle the clock frequency (reducing hashrate to reduce heat) or shut down the miner entirely.

Common causes and solutions:

• Dust buildup: The number one cause. Clean the heatsinks, fans, and airflow path with compressed air. See quarterly maintenance.
• Failed fan: A seized or slow fan cannot cool the hashboards. Replace immediately.
• Degraded thermal paste: After 12–18 months, thermal paste dries out and loses conductivity. Replace with fresh non-conductive paste (Arctic MX-5 or equivalent).
• High ambient temperature: If your room temperature exceeds 35°C, the M30S cannot maintain safe chip temperatures even with perfect airflow. Improve room ventilation, add exhaust ducting, or reduce ambient temperature.
• Recirculated hot air: If the miner’s exhaust is being drawn back into its own intake (or a neighboring miner’s intake), you get thermal stacking. Ensure exhaust air exits the room.
• Heatsink contact failure: If a heatsink has partially detached from a hashboard (loose mounting screws, broken clip), chips under that section will overheat while others stay cool. This shows as uneven temperature readings across a single board.

Network Connectivity Issues

Network problems on the M30S are usually simple, but they can mimic more serious issues. A miner that cannot reach its pool shows zero hashrate on the pool dashboard, which looks identical to a hardware failure from the monitoring side.

• Check physical connection: Verify the Ethernet cable is firmly seated in the RJ45 port. Check for bent pins in the port. Try a different cable.
• Check link lights: The Ethernet port should show activity lights. No lights = no link layer connection.
• DHCP vs. static: If you switched to a static IP and then changed routers or subnets, the M30S will have an IP that does not match your network. You may need to factory reset the control board (pinhole reset button, hold 10+ seconds) to revert to DHCP.
• DNS resolution: If the miner can ping gateway IPs but cannot connect to pool URLs, DNS is the problem. Use IP-based pool addresses as a workaround, or fix your DNS configuration.

Whatsminer Error Code Reference

WhatsMinerOS uses a different error code format than Antminer. Here are the most common M30S error codes and their meanings:

Hashboard Repair

Hashboard repair is the deepest level of M30S maintenance. Everything up to this point — cleaning, fan replacement, connector reseating — is accessible to any home miner with basic tools and patience. Hashboard repair requires specialized equipment, component-level electronics knowledge, and a willingness to work under magnification on components smaller than a grain of rice. If that description gives you pause, skip to the When to Contact D-Central section. There is no shame in knowing your limits.

Hashboard Removal

The M30S hashboard removal process differs from Antminer. The tighter chassis integration and 4-pin connectors require a different approach:

1. Power off, unplug, wait 10 minutes. Non-negotiable.
2. Remove chassis cover screws. Note screw locations — some M30S revisions use different screw lengths in different positions. Take a photo or organize screws by position.
3. Disconnect fan connectors from the control board if they obstruct hashboard access.
4. Disconnect the 4-pin hashboard connector. These connectors are firm — do not yank. Grip the connector body (not the wires) and pull straight back with steady, even pressure. Pulling at an angle can bend connector pins.
5. Remove hashboard mounting screws securing the board to the chassis frame.
6. Slide the hashboard out carefully. The heatsinks add width — angle the board as needed to clear the chassis opening. Do not force it.
7. Place the removed hashboard on an ESD mat immediately. Never set it on an ungrounded surface.

Visual Inspection Checklist

Before connecting any test equipment, a thorough visual inspection under magnification catches many common failures:

• PCB discoloration: Brown or yellow spots on the PCB indicate localized overheating. Mark these areas — the component above or below the discoloration is the likely failure point.
• Swollen capacitors: Look for capacitors with domed or bulging tops (they should be flat). Swollen caps need replacement.
• Cracked solder joints: Under magnification, examine BGA chip perimeters for cracked or fractured solder. Thermal cycling (the repeated heating/cooling of normal operation) eventually cracks marginal joints.
• Corroded pads/traces: Moisture ingress causes corrosion, especially in humid environments. Green or white deposits around component pads indicate corrosion damage.
• Physical damage: Dents, scratches, or cracks in the PCB from shipping damage or mishandling.
• Thermal paste contamination: Dried or excess thermal paste that has migrated onto component leads or connector pads can cause short circuits or poor connections.
• Heatsink contact patterns: Remove the heatsink and examine the thermal paste impression. Full, even coverage is good. Dry spots or bare areas indicate mounting pressure problems.

Voltage Domain Testing

Each M30S hashboard is organized into voltage domains, with groups of ASIC chips sharing power regulation circuitry. Testing voltage at each domain helps localize failures to specific chip groups.

1. Identify test points: The hashboard PCB has labeled test points for each voltage domain. Consult the hashboard schematic for your specific M30S revision (schematics vary between hardware revisions).
2. Set multimeter to DC voltage mode.
3. Measure each domain voltage with the hashboard powered (using a test fixture — NOT in the miner under AC power). Compare readings against expected values.
4. Look for anomalies: A domain reading 0V indicates a dead short or open circuit in that domain. A domain reading significantly low suggests a partially shorted chip or failed LDO regulator.
5. Resistance check: With the hashboard unpowered, measure resistance across each voltage domain. Compare domain-to-domain — they should all read similar resistance. A domain with significantly lower resistance has a shorted component.

ASIC Chip Testing Methodology

Once you have localized a fault to a specific voltage domain, individual chip testing identifies the failed component:

1. Temperature scan: With the hashboard powered on a test fixture, use a thermal camera or contact thermometer to scan chip temperatures across the suspect domain. A chip running significantly hotter or cooler than its neighbors is likely failed.
2. Signal tracing: Using an oscilloscope, trace the clock (CLK) and data signals through the chip chain in the affected domain. The signal will propagate normally through good chips and stop or degrade at the failed chip.
3. Resistance measurement: Measure resistance across individual chip VDD and GND pads. A chip showing near-zero resistance is shorted internally.

Common M30S Failure Patterns

After repairing hundreds of M30S hashboards, certain failure patterns emerge consistently:

• BGA solder joint cracking: The most common failure on M30S boards. Thermal cycling causes solder balls under ASIC chips to develop micro-cracks. The chip intermittently loses contact, causing hashrate drops or chain errors. Reflow or reball of the affected chip resolves this.
• LDO regulator failure: The low-dropout regulators that supply individual voltage domains can fail, taking out an entire chip group. Symptoms: one domain reads 0V while others are normal. Replace the failed LDO.
• Decoupling capacitor failure: Small ceramic capacitors near ASIC chips can crack (from PCB flexing or thermal stress) and short-circuit, dragging down the entire voltage domain. Visually inspect under magnification — cracked caps sometimes show a hairline fracture visible under 10x magnification.
• Connector pin damage: The 4-pin connectors see significant current and can develop hot spots, especially if they were not fully seated. Carbon buildup on pins increases resistance, causing voltage drop and intermittent detection failures.
• PSU-side failure affecting hashboards: An integrated PSU developing voltage ripple or instability can damage hashboard components over time. If multiple boards develop similar faults simultaneously, suspect the PSU as the root cause.

BGA Rework on MicroBT Chips

Replacing a failed MicroBT ASIC chip is a professional-level repair requiring BGA rework equipment. This is not a beginner task.

Overview of the process:

1. Pre-heat the board on a BGA rework station’s bottom heater to approximately 150°C.
2. Apply flux around the perimeter of the chip to be removed.
3. Heat the chip with the top nozzle to reflow temperature (typically ~230°C for lead-free solder, ~183°C for leaded). Use the rework station’s thermal profile — do not just blast heat.
4. Lift the chip with vacuum pickup when solder is fully reflowed.
5. Clean the pads — remove residual solder with desoldering wick and flux.
6. Prepare the replacement chip — if the replacement does not have fresh solder balls, reball it using a stencil and solder paste.
7. Place the new chip with precise alignment. BGA alignment is critical — even 0.1mm offset can cause bridged connections.
8. Reflow the new chip following the thermal profile.
9. Clean flux residue with IPA and inspect under magnification.
10. Test the board on a hashboard test fixture before reinstalling in the miner.

Fan Replacement

Fan replacement is the most common and most accessible repair on the M30S. With only two fans handling all cooling, each fan is a single point of semi-failure — when one dies, you lose 50% of cooling capacity and the miner shuts down.

Fan Specifications

Replacement Procedure

1. Power off and unplug. Wait 10 minutes for capacitor discharge.
2. Remove the fan guard/grille (if applicable — some M30S revisions have removable grilles, others have fixed grilles requiring chassis disassembly).
3. Disconnect the 4-pin fan connector from the control board. Note which port the fan was connected to (front fan vs. rear fan — they connect to different header positions on the control board).
4. Remove the fan mounting screws (typically 4 screws per fan). Support the fan while removing the last screw to prevent it from dropping onto hashboards.
5. Install the replacement fan. Ensure correct orientation — the airflow arrow printed on the fan housing must point from front-to-rear (intake at front, exhaust at rear). Reversing a fan creates a dead zone in the airflow path.
6. Secure with mounting screws. Tighten evenly but do not overtighten — fan housings are plastic and can crack.
7. Connect the 4-pin fan connector to the correct header position on the control board.
8. Power on and verify. Both fans should spin up immediately. Check the web interface for normal RPM readings and absence of fan error codes.

PSU Diagnostics & Repair

The integrated PSU is the component that most differentiates the M30S repair experience from Antminer work. On an Antminer, you can swap the APW PSU in minutes, test it independently, or bypass it entirely with a bench power supply. On the M30S, the PSU is part of the machine. Diagnosing and repairing it happens with the chassis partially open.

Built-In PSU Voltage Rails

The M30S integrated PSU converts AC mains input to multiple DC voltage rails:

• Main hashboard power rail: This is the high-current rail that feeds the ASIC chips. Voltage varies by model variant and is set by the firmware’s voltage profile.
• Control board power rail: Lower-current 3.3V and 5V rails for the control board SoC, Ethernet PHY, and management circuitry.
• Fan power rail: 12V supply for the PWM-controlled fans.
• Standby rail: A low-power standby voltage that keeps the control board alive even when hashboards are powered down.

Testing with a Multimeter

1. No-load test (miner unpowered, PSU only): Some M30S PSUs will not output DC voltage without a minimum load. If the PSU has a standby rail, you should be able to measure 3.3V or 5V on the control board power connector even without hashboards drawing power.
2. Loaded test (miner running): With the chassis open and miner running, carefully measure DC voltage at the hashboard power connectors. All three hashboards should show the same voltage (within 2% of each other). A board showing significantly lower voltage has a connection issue or is drawing excessive current due to a short.
3. AC input verification: Measure AC voltage at the C19 inlet (from outside the chassis — do NOT open the PSU section while powered). Should read between 200–277V AC.
4. Ripple test (advanced): Using an oscilloscope on AC coupling mode, measure voltage ripple on the DC output. Excessive ripple (more than 100mV peak-to-peak) indicates failing PSU capacitors and can cause hashboard instability.

Common PSU Failures

• Electrolytic capacitor failure: The most common PSU failure mode. Capacitors age under heat stress, lose capacitance, and develop increased ESR (equivalent series resistance). Symptoms: increased output ripple, inability to deliver full power, and eventually complete failure. Visually detectable when caps are physically swollen.
• Inrush current damage: Power surges or unstable grid power can damage the PSU input stage. Surge protectors rated for high-wattage loads are recommended.
• Fan-related thermal damage: If the PSU has its own internal cooling (some revisions do), a failed PSU cooling fan causes the PSU to overheat and degrade. Listen for additional fan sounds from the PSU area.
• Connector pin burnout: The high-current DC output connectors can develop hot spots where pins make poor contact, leading to arcing and carbon buildup. Inspect pins for discoloration and pitting.

When to Replace vs. Repair the PSU

Firmware Management

WhatsMinerOS is MicroBT’s proprietary firmware platform. It handles everything from chip initialization and frequency control to temperature monitoring and pool communication. Keeping firmware current is important for stability, security, and sometimes performance. But firmware updates on Whatsminer hardware are a different process from Antminer — and the ecosystem of third-party firmware is much more limited.

Stock WhatsMinerOS Updates

MicroBT releases firmware updates through their official channels. Updates may include bug fixes, performance optimizations, security patches, and support for new pool protocols.

How to check your current firmware version:

1. Log into the WhatsMinerOS web interface
2. Navigate to the System or Status page
3. The firmware version is displayed prominently (format varies, e.g., 20230101.22.REL)

Firmware Update Procedure

The M30S firmware update process differs from Antminer’s web-based upload. There are two primary methods:

Method 1: Web Interface Upload

1. Download the correct firmware file from MicroBT’s official source. Critical: Ensure the firmware matches your exact model (M30S, M30S+, or M30S++). Using the wrong firmware can brick the control board.
2. Log into the WhatsMinerOS web interface.
3. Navigate to System > Firmware Upgrade (exact menu path varies by WhatsMinerOS version).
4. Select the firmware file and click Upload.
5. Wait for the update to complete. Do not power off or disconnect during the update. The miner will automatically reboot when finished.
6. After reboot, log back in and verify the firmware version has been updated.
7. Re-check your pool configuration — some firmware updates reset pool settings.

Method 2: WhatsMinerTool (Bulk Update)

1. Download and install MicroBT’s WhatsMinerTool utility on a Windows PC on the same network.
2. The tool will discover all Whatsminer devices on the local network.
3. Select the devices to update, choose the firmware file, and initiate the batch update.
4. This method is essential for operations managing multiple Whatsminers — updating one at a time via the web interface is not scalable.

Factory Reset Procedure

If the WhatsMinerOS web interface becomes inaccessible (due to a bad firmware update, corrupted settings, or forgotten password), a factory reset returns the control board to default settings.

1. Locate the reset button: On the M30S control board, there is a small recessed pinhole button. You will need a paperclip or SIM eject tool.
2. With the miner powered on, press and hold the reset button for 10+ seconds.
3. The miner will reboot and return to factory default settings (DHCP network, default credentials, cleared pool configuration).
4. After reset, you will need to rediscover the miner’s IP address (it will request a new DHCP lease) and reconfigure all settings.

SD card recovery (last resort): If a factory reset does not restore functionality, MicroBT provides recovery firmware images that can be loaded via an SD card inserted into the control board’s SD slot. This effectively re-images the control board’s operating system. Download the recovery image from MicroBT support, write it to a FAT32-formatted SD card, insert it into the powered-off control board, and power on. The control board will boot from the SD card and reflash its internal storage.

Third-Party Firmware — Limited Options

Unlike the Antminer ecosystem, which has a rich third-party firmware landscape (Braiins OS+, VNish, LuxOS, and others), the Whatsminer M30S has significantly more limited third-party firmware support. MicroBT’s hardware uses different bootloader security and firmware signing compared to Bitmain, which makes third-party firmware development more difficult.

Some autotuning and optimization firmware does exist for Whatsminer, but options are fewer and community support is thinner. If firmware customization is a priority for your operation (autotuning, power capping, dev-fee-free mining), Antminer hardware currently offers a more mature ecosystem.

For most M30S operators, staying on stock WhatsMinerOS is the practical recommendation. MicroBT’s stock firmware is generally well-optimized, and the limited third-party options mean the risk/reward ratio of non-stock firmware is less favorable than on Antminer.

M30S vs. Antminer: Repair Technician Reference

For technicians who work on both platforms, this section highlights the key differences that affect your repair workflow. If you have years of Antminer experience and are picking up Whatsminer repair for the first time, these are the things that will trip you up.

Additional Tools for Whatsminer Repair

If your repair bench is currently set up for Antminer-only work, you will need to add the following for Whatsminer support:

• Whatsminer hashboard test fixture: Your ARC Kit or Bitmain PT2 will not work. You need a fixture designed for M30S hashboard connectors and pinout.
• C19/C20 power cord: Your C13/C14 cords for testing APW PSUs will not fit the M30S. Keep C19/C20 cords in your parts inventory.
• MicroBT ASIC chip inventory: Bitmain BM1398 chips do not go on Whatsminer boards. You need MicroBT-specific replacement chips matched to the M30S variant.
• Updated schematics: Whatsminer hashboard schematics and test point diagrams. These are less commonly circulated than Antminer schematics — check MicroBT’s service partner channels or repair community forums.
• WhatsMinerTool software: For firmware recovery and batch configuration. Runs on Windows.

Parts Sourcing

Sourcing Whatsminer parts is generally harder than Antminer parts, primarily because Bitmain has a much larger global installed base and therefore a more developed secondary parts market. For M30S parts, your options include:

• MicroBT directly: For authorized service partners.
• Specialized mining hardware distributors: Companies like D-Central that stock both Antminer and Whatsminer parts.
• Donor machines: Purchasing a non-functional M30S as a parts donor is sometimes more cost-effective than sourcing individual components — especially for hashboards.
• Component-level sourcing: For passive components (capacitors, resistors, MOSFETs), standard electronics distributors carry compatible parts. For ASIC chips, you need MicroBT-specific sources.

When to Contact D-Central

Not every repair needs a professional — but some absolutely do. Knowing the line between a confident DIY fix and a costly mistake saves you both money and hardware. Here is how we think about it:

D-Central Technologies offers professional ASIC repair services from our facility in Laval, Quebec. We repair Whatsminer hardware alongside Antminer, Innosilicon, and Canaan equipment — we are manufacturer-agnostic and platform-fluent. Over 2,500 miners repaired since 2016, including a growing number of Whatsminer M30S units as their installed base matures and maintenance cycles begin.

Frequently Asked Questions

Keep Your M30S Hashing

The Whatsminer M30S series proved that Bitmain does not have a monopoly on building excellent Bitcoin miners. MicroBT’s integrated design, Samsung 8nm silicon, and clean industrial engineering produced a platform that earned the trust of mining operations worldwide. With proper maintenance, your M30S will mine profitably for years. With neglect, it becomes an expensive paperweight that generates zero hashrate and contributes nothing to Bitcoin’s decentralized security.

The maintenance playbook is straightforward: monitor daily, clean monthly, deep-inspect quarterly, and replace thermal paste annually. The M30S’s two-fan design makes fan health more critical than on an Antminer — a single failed fan means an immediate shutdown, not a graceful degradation. Stay ahead of fan wear. Keep your heatsinks clean. Watch your temperature readings like they are vital signs — because for your miner, they are.

When something does break — and something eventually will, because physics does not care about your uptime targets — use the diagnostic procedures in this guide to identify the problem quickly. Simple fixes (fan replacement, connector reseating, firmware recovery) are DIY-accessible. Complex repairs (BGA rework, PSU capacitor replacement, voltage domain diagnosis) belong with a professional repair facility that has the tools, the parts, and the experience to do it right the first time.

Every Whatsminer M30S that keeps hashing is another contribution to Bitcoin’s decentralized hashrate distribution. Every home miner who learns to maintain their own equipment reduces dependence on centralized mining operations and takes another step toward the sovereign, decentralized mining ecosystem that Bitcoin demands. The M30S is your tool. This guide is your manual. The network is counting on you.

D-Central Technologies is here when you need us. We stock Whatsminer replacement parts, we repair hashboards and PSUs at our facility in Laval, Quebec, and we are a phone call away at 1-855-753-9997. We have been keeping miners hashing since 2016 — Antminer, Whatsminer, Innosilicon, Canaan, all of them. We are Canada’s Bitcoin Mining Hackers, and MicroBT hardware is no exception.

Mine on.