Antminer S21 XP Repair — Professional ASIC Repair by D-Central
The Bitmain Antminer S21 XP is the flagship of the S21 lineup — a 270 TH/s air-cooled SHA-256 miner operating at an extraordinary 13.5 J/TH efficiency. That 12% improvement over the S21 Pro is achieved through a redesigned hashboard architecture: 91 BM1370P chips per board organized into 13 domains of 7 chips each, for a total of 273 chips across three hashboards. The S21 XP also introduces a detachable OLED display on the control board panel for quick at-a-glance status monitoring. This is the most advanced air-cooled Bitcoin miner Bitmain has produced — and repairing it demands equally advanced expertise.
D-Central Technologies has been at the forefront of ASIC repair since 2016. As Canada’s Bitcoin Mining Hackers, we track every new Bitmain platform from announcement through production deployment, investing in the test fixtures, chip-level tools, and technical training to service these machines from day one. The S21 XP’s BM1370P architecture, denser hashboard layout, and new control board features are all within our repair capabilities.
Antminer S21 XP Specifications
| Specification | Details |
|---|---|
| Algorithm | SHA-256 (Bitcoin, Bitcoin Cash) |
| Hashrate | 270 TH/s |
| Power Consumption | 3,645W (±5%) |
| Efficiency | 13.5 J/TH |
| ASIC Chip | BM1370P (91 chips per hashboard) |
| Total Chips | 273 (3 hashboards x 91) |
| Domain Layout | 13 domains per hashboard, 7 chips per domain |
| Domain Voltage | ~1.04V per domain |
| Hashboard Model | A3HB70501 |
| Control Board | Amlogic A113D with detachable OLED display |
| Power Supply | APW17 |
| Input Voltage | 220–277V AC |
| Cooling | Air-cooled (dual fan) |
| Noise Level | 76 dB |
| Dimensions | 449 x 219 x 293 mm |
| Weight | 18.7 kg |
| Operating Temperature | -20°C to 45°C |
Common Antminer S21 XP Issues and Symptoms
The S21 XP’s 91-chip hashboard design represents the highest chip density in any air-cooled Antminer. More chips per board means more potential failure points and more complex diagnostics. These are the issues we encounter most frequently:
Incomplete Chip Detection
The most common S21 XP fault. When the kernel log reports “find x asic” where x is less than 91, it means one or more chips on that hashboard are not being detected. The R:1 error code accompanies this in full-machine tests. Root causes include failed BM1370P chips breaking the signal chain, faulty solder joints (which can sometimes be resolved by reflowing the chip), or damaged signal traces. The S21 XP signal chain follows specific directions: CLK, CI, BI, and RST signals transmit forward from chip 1 to chip 91, while the RO signal transmits in reverse from chip 91 to chip 1. Understanding this directional flow is essential for efficient fault isolation.
Overheating and Thermal Protection
At 3,645W across three hashboards with 91 chips each, the S21 XP generates serious heat. The machine will shut down automatically when chip temperatures exceed safe limits. With 273 chips to cool, any degradation in thermal paste, heatsink contact, airflow, or fan performance has immediate consequences. The BM1370P chips are highly sensitive to thermal conditions — operating them without proper heatsink attachment during testing or repair will burn the board. Common thermal failure triggers: worn thermal conductive gel, dust accumulation, ambient temperature above 45°C, degraded fan bearings, and contamination from previous repair flux residue.
BM1370P Chip Failures
Individual chip failures on the S21 XP’s A3HB70501 hashboard take a domain offline and reduce overall hashrate. Each 7-chip domain operates at approximately 1.04V — extremely tight margins where a single failed chip creates voltage irregularities across the domain. If a failed chip is identified, our technicians first attempt a reflow (heating each solder joint to a molten state to restore pad contact). If the fault persists after reflow, the chip is replaced with a matching BM1370P component.
Hashboard Communication Failures
If the S21 XP detects fewer than 3 hashboards, the issue usually lies in the cable connection between the hashboard and control board, or in the hashboard’s communication interface. The S21 XP uses a different control board variant from the standard S21 (supporting the detachable OLED display), so control board compatibility must be verified during diagnosis.
Fan and Cooling System Failures
The S21 XP’s dual-fan air cooling system must dissipate 3,645W of heat continuously. Fan motor wear, bearing failure, connector damage, or control board fan circuitry faults trigger warnings and eventual shutdown. Given the S21 XP’s higher power draw compared to the S21 and S21 Pro, cooling margin is tighter — a partially degraded fan that might be tolerable in a lower-wattage miner will cause thermal issues in the XP.
Control Board and Firmware Issues
Firmware corruption, NAND flash degradation, OLED display connector issues, and network interface failures. The S21 XP’s firmware is more complex than earlier S21 models due to the different hashboard architecture (91 chips vs. 65 or 108) and additional display hardware. Firmware issues can mimic hardware faults — proper diagnosis distinguishes between the two before any board work begins.
Power Supply Compatibility
The S21 XP draws 3,645W — the highest in the S21 air-cooled family. It requires the APW17 power supply and a stable 220–277V input. Marginal power supplies, long or undersized power cables, and facility voltage drops under load can cause intermittent hashboard detection failures, chip errors, and gradual component degradation.
Our Repair Process
The S21 XP demands the highest level of repair precision in the air-cooled Antminer lineup. Here is how we handle every unit at our Laval, Quebec facility:
1. Intake and Visual Inspection
We photograph and document the unit’s condition on arrival. Visual inspection covers physical damage, heatsink integrity, connector condition, dust and contamination levels, and any evidence of prior repair work.
2. Comprehensive Diagnostics
Each A3HB70501 hashboard is tested on our BM1370 test fixture: chip enumeration (all 91 chips), domain voltage measurements across all 13 domains, signal chain integrity (forward and reverse paths), temperature sensor validation, and thermal imaging under load. The control board undergoes firmware verification, OLED display testing, hashboard communication checks, and network diagnostics.
3. Transparent Quote
You receive a detailed diagnostic report listing every identified fault, the proposed repair for each, itemized costs, and estimated turnaround time. Repair only proceeds with your explicit approval.
4. Precision Board-Level Repair
Repairs are performed with professional BGA rework equipment: BM1370P chip reflow or replacement, thermal conductive gel reapplication with proper heatsink reattachment, LDO regulator replacement, signal trace repair, domain junction troubleshooting, and control board repair. Every repaired chip surface is thoroughly cleaned of flux residue before heatsink reattachment to prevent future thermal issues.
5. Dual-Pass Testing and Burn-In
Per the S21 XP repair protocol, every repaired hashboard must pass testing twice: once after repair and again after a complete cool-down period. This dual-pass approach catches marginal repairs that would fail under thermal cycling. The fully assembled unit then runs an extended burn-in to verify stable 270 TH/s output with consistent temperatures.
6. Return Shipping
Your S21 XP is securely packaged and returned with complete documentation of all diagnostics and repairs.
Repair Pricing
S21 XP repair pricing reflects the complexity of the unit and the specific faults identified during diagnostics. As the most advanced air-cooled Antminer, repair costs may be slightly higher than the standard S21 or S21 Pro due to component costs and repair complexity. We provide exact pricing after diagnostic testing — no estimates, no hidden fees.
For a preliminary estimate, use our ASIC Repair Cost Estimator.
Why D-Central for Antminer S21 XP Repair
Cutting-edge BM1370P repair capability. The S21 XP is the newest and most advanced air-cooled Antminer. D-Central has invested in the specific test fixtures, chip testers, and technical expertise required to service the A3HB70501 hashboard and its 91-chip, 13-domain architecture. We are one of the few Western repair facilities equipped for this platform.
8+ years of Antminer repair heritage. We have repaired every generation of Antminer since the S9 era. That accumulated knowledge — understanding how Bitmain evolves their designs, what fails and why, and how to troubleshoot efficiently — is irreplaceable. The S21 XP is an evolution, not a revolution, and we understand its lineage.
Complete parts inventory. BM1370P chips, A3HB70501 hashboards, Amlogic A113D control boards (XP variant), APW17 power supplies, fans, thermal materials, temperature sensors, and LDO regulators — all in stock at our Canadian facility.
North American turnaround. Ship from anywhere in Canada or the US to our Laval, Quebec repair center. No customs, no international shipping delays, no language barriers. Reach us at 1-855-753-9997.
Warranty-backed repairs. Every repair includes a warranty on our workmanship and the components we install. If the same issue returns within the warranty period, we make it right at no additional cost.
Frequently Asked Questions
How long does an S21 XP repair take?
Typical turnaround is 5–12 business days. The S21 XP’s dual-pass testing protocol (test, cool, retest) adds time compared to simpler models, but it ensures repair quality. Simple issues like fan replacement can be completed in 1–3 days. Complex multi-chip repairs may take up to 2–3 weeks. We provide timeline estimates with your diagnostic report.
Do you warranty S21 XP repairs?
Yes. All D-Central repairs are warranty-backed, covering our workmanship and the replacement components installed. If the repaired issue recurs within the warranty period, we fix it at no charge.
How do I ship my S21 XP for repair?
Contact us first to open a repair ticket. We will provide our Laval, Quebec shipping address and intake instructions. Pack the unit in its original box if available, or use a sturdy box with foam protection on all sides. The S21 XP weighs 18.7 kg, so ensure the box is rated for the weight. Remove the APW17 PSU to reduce shipping cost unless you suspect a PSU issue. Include a note describing the problem.
What does S21 XP repair cost?
Pricing depends on the diagnosis. Fan or firmware repairs: $50–$150. Single-chip hashboard repair: $200–$500. Multi-chip or complex board-level work: $500–$1,000+. The S21 XP’s BM1370P chips and A3HB70501 hashboards are premium components, which is reflected in parts costs. We always quote exact pricing after diagnostics. Use our ASIC Repair Cost Estimator for a preliminary figure.
Should I attempt DIY repair on an S21 XP?
We strongly advise against it unless you have professional BGA rework equipment and specific experience with BM1370P chips. The S21 XP operates at ~1.04V domain voltages with 91 chips per board in a signal chain where directional signal flow must be traced correctly (CLK/CI/BI/RST forward, RO reverse). Incorrect chip replacement, improper reflow, or flux contamination will cause additional damage. The dual-pass testing requirement also means you need proper test fixtures to verify repairs.
What does the R:1 error code mean on my S21 XP?
R:1 indicates that the whole-machine test failed. This is typically triggered by incomplete chip detection (fewer than 91 chips found on a hashboard) or by chip temperatures exceeding the safety threshold. It is a general failure code — our diagnostics determine the specific root cause, whether it is a chip failure, thermal issue, signal chain break, or firmware problem.
Can you repair just one S21 XP hashboard?
Absolutely. You can send a single A3HB70501 hashboard if you have already identified the faulty board. We also accept full units for complete diagnosis. Additionally, we sell tested replacement hashboards and individual components for those with in-house repair capability.
Is the S21 XP OLED display repairable?
Yes. The detachable OLED display is a control board component. If the display fails or shows incorrect data, it can be replaced or the connector reseated. This does not affect mining operation — the web interface remains the primary management tool — but we can restore the display functionality during a repair service.
Get Your Antminer S21 XP Mining Again
The S21 XP is the most powerful air-cooled Bitcoin miner on the market. At 270 TH/s and 13.5 J/TH, every hour of downtime represents significant lost revenue. D-Central has the expertise, the BM1370P parts, and the precision repair process to restore your XP to peak performance.
Contact D-Central for a repair quote or call us at 1-855-753-9997.