Bitmain APW8 Power Supply Unit Repair Guide & Components List

Bitmain APW8 Power Supply Unit Repair Guide & Components List (2026 Update)

The Bitmain APW8 is the legacy PSU for the Antminer S15 / T15 generation — built around a dedicated PFC front-end (NCP1654BD65R2G) and a flyback topology driven by the SI8016HSP8 PWM controller, with a 16-20V DC output range that distinguishes it from the newer APW12 series (12-15V). Many APW8 units are still running across older S15 / T15 fleets in low-cost-power environments. This guide covers the 18 most vulnerable components on the APW8, the legacy-PSU diagnostic workflow, and the full repair playbook with direct sourcing links — companion to our Bitmain APW12 PSU repair guide for the broader Bitmain PSU family.

Why APW8 PSU Repair Matters in 2026

The APW8 powered the S15 / T15 generation of Antminers — a fleet that remains in operation in many low-cost-power environments. Replacement APW8 units are increasingly constrained in supply (Bitmain has long stopped volume manufacturing of this generation), which means component-level repair is the only realistic path to keep these PSUs producing. Many APW8 chip-level failures are caused by aged silicon (especially the 600V primary MOSFETs and the PFC controller) plus dried bulk capacitors — all replaceable parts with available repair stock.

Compatible Antminer Models

The APW8 series powered the following Antminer models across the S15 / T15 generation:

• S15 family: S15 28T / 27T / 26T (BM1391 7nm chip generation)
• T15 family: T15 23T

The APW8 ships in the 16-20V DC output range, distinguishing it from the newer APW9 / APW9+ (for S17 generation, 14.5-21V) and the APW12 (for S19 generation, 12-15V). The APW3 (now deprecated per our memory rules) and APW7 are the predecessors. The output voltage range and connector pinout are PSU-generation-specific — an APW8 and an APW12 are not directly interchangeable on a given miner chassis.

For the newer S19-class PSU, see our APW12 PSU repair guide. The APW9 / APW9+ used on S17-class miners shares some chip-level components with the APW8 (SI8016HSP8 PWM controller, IX4424NTR gate driver, TPHR8504PL synchronous MOSFET) — making a small bench inventory cover both PSU generations.

APW8 PSU Architecture at a Glance

The APW8 is a PFC-fronted LLC resonant switching supply with digital monitoring. Bitmain's documented architecture is: AC input 200-240V → EMI / LC filter → rectifier bridge → PFC stage → VBUS filter large capacitor → main switch MOS → LLC-DC switching circuit → isolation drive → DC drive circuit → synchronous rectification filter → DC main voltage output. A separate 12V auxiliary circuit (T1 transformer) provides standby power and fan supply. Key architectural elements:

Specifications (16.32-20.04V variant for S15 / T15)

• AC input: 200-240V single-phase, C14 connector (triangle-shape, requires C13 AC cable)
• Main DC output: 16.32V to 20.04V adjustable via I²C, maximum current 95A
• Auxiliary DC output (SB): 12V fixed, up to 5A, delivered via PCIE 6-pin connector (yellow positive on pins 1/2/3, black negative on pins 4/5/6)
• 4-Pin signal terminal: I²C (SDA / SCL) for voltage control + EN signal (active-low — pull EN to GND to enable the main output)
• Default voltage test mode: short J15 PIN 4-5 (EN to GND) to enable the main 16.32V output without a control board
• Operating temperature: full-load operation up to 60°C ambient
• Output terminals: 4× PCB-33 copper soldering terminals (90-degree side-foot binding posts, M4 high-current horizontal fixing). The 2 terminals close to the air outlet are positive; the 2 near the signal terminal are negative.
• Protection: under-voltage, short-circuit, overload, over-temperature, with automatic recovery after fault removal

Note: the APW8 series also ships in 8V-9.2V and 10V-11V variants for older Antminer generations. This guide focuses on the 16.32-20.04V variant used on S15 / T15 miners. The output voltage range is set by the PIC control firmware and is PSU-variant-specific.

Component-level architecture

• Input stage: F1 fuse (AC input), U2 rectifier bridge (AC-to-DC rectification at the input), surge protection resistor, AC input relay.
• PFC (Power Factor Correction) stage: NCP1654BD65R2G dedicated PFC controller (SO-8 package, 65 kHz fixed frequency). PFC switch MOS at Q4, with D5 / D6 / D7 diodes on the PFC stage. The PFC large capacitor (positions C16 / C17) holds the bus voltage at 370-380V DC under normal operation.
• Auxiliary 12V circuit: voltage detection startup at R33 (47K) connected to HV via D1 / D2. 12V main switch MOS at Q5, with driver IC U5, diodes D8 / D9, and the 12V transformer at T1. When 12V is normal and PFC large capacitor is at 370-380V, the VCC 12V main control supply automatically turns on.
• Main switch MOS stage: Q6, Q14, Q15, Q16 form the primary switching half-bridge or full-bridge depending on production variant. Built around the 600V-class MOSFETs TK62N60W, K39N60W5 / TK39N60W5 (TO-247, 600V / 38.8A), and TK20A60W5 (600V / 20A).
• LLC-DC switching circuit: the LLC resonant converter stage transforms the high-voltage bus into the isolated output rail through the main transformer.
• Main PWM control: SI8016HSP8 high-voltage PWM controller (SOP-8) — same controller is shared with APW9 / APW9+. PWM circuit ICs at U9 / U10 / U11; each requires its VCC supply of 12V to operate. The T4 drive transformer isolates the PWM drive signal between primary and secondary sides.
• Gate driver: IX4424NTR / IX4424N dual low-side MOSFET driver provides gate-drive signals to the primary switching MOSFETs. Same driver is used on APW7 / APW9 / APW9+.
• Synchronous rectification (output stage): Q17 / Q18 / Q19 / Q20 output synchronous rectification MOSFETs handle the secondary-side switching. Built around TPHR8504PL (40V N-channel) shared across APW7 / APW8 / APW9 / APW12.
• Output diode: SCS210AMC 650V / 10A SiC diode (TO-220 through-hole) on the secondary path.
• Output filter: 1000µF 16V output filter capacitors on the auxiliary 12V rail.
• Protection: MBR0540 Schottky power rectifier (0.5A / 40V SOD-123) handles low-voltage signal-path protection.
• Voltage reference / feedback: ZTL431BFTA adjustable shunt voltage reference (2.5V / 100mA, SOT-23-3) sets the output regulation point through the feedback network.
• PIC control / regulation: PIC16F1704-I/SL 8-bit microcontroller (7KB Flash, 14-pin) handles host I²C communication, voltage regulation commands, fault reporting, and basic supervision. Same MCU family used on Antminer hashboards and on the newer APW12 — single PIC stock covers cross-platform repair.
• Magnetics: PQ2620 main power transformer (primary stage), PQ5030T auxiliary transformer (12V supply). JB1250W-L (1L2 marking) and HS151025 in the input / standby chain. T4 drive transformer for the PWM isolation. T1 in the 12V auxiliary path.
• Small-signal support: MMBT3906 PNP (40V / 200mA, SOT-23) and DSS5540X PNP BJT (40V / 4A, SOT-89) handle protection-circuit and gate-drive support functions.

Most Common APW8 PSU Failure Modes

• No DC output, fan spinning, AC LED green — first check the M6 copper-bar bolts on the hashboard-side output. Loose busbar bolts on Bitmain PSUs follow a universal failure pattern (factory torque often ships below the 2.5-3.5 N-m spec range, joints settle after thermal cycling). Re-torque to 3.0 N-m before opening the PSU case.
• PSU dead after AC input, fan does not start — check the AC input fuse first. A blown fuse usually points to a downstream short on the primary switching stage (TK62N60W, K39N60W5, or TK20A60W5 MOSFETs).
• Hard short on primary switching — typically a failed TK62N60W, K39N60W5, or TK20A60W5 MOSFET. Test in diode mode before powering up — a healthy MOSFET shows 0.3-0.6V drop between drain and source.
• PFC controller fault — failed NCP1654BD65R2G prevents the front-end PFC stage from regulating. The PSU may still come up with the auxiliary supply but the main rail will be unstable under load.
• Main PWM controller fault — failed SI8016HSP8 prevents the primary stage from oscillating; no switching means no transformer output.
• Gate driver failure — failed IX4424NTR / IX4424N dual MOSFET gate driver leaves the primary MOSFETs un-driven; PWM signal exists but the MOSFETs don't switch.
• Output voltage out of spec — degraded ZTL431BFTA voltage reference drifts the regulation point, producing wrong output voltage even when the rest of the PSU is healthy.
• Secondary rectification failure — failed SCS210AMC SiC diode or TPHR8504PL sync MOSFET produces low or unstable output voltage.
• Communication failure with control board — failed PIC16F1704 microcontroller blocks the I²C signalling between the PSU and the miner. The miner reports "PSU not detected" or similar.
• Output voltage drops under load — degraded 1000µF 16V output capacitors no longer hold rail voltage during transient current draw. Visual inspection for swollen tops or leaked electrolyte is the first check.

Critical Components — Function & Failure Behaviour

NCP1654BD65R2G PFC Controller

The NCP1654BD65R2G is a fixed-frequency 65 kHz PFC controller in SO-8 package. The PFC stage is what distinguishes the APW8 from the simpler quasi-resonant APW7 — the dedicated PFC controller shapes the input current to maintain a high power factor under varying load, which both improves efficiency and meets utility-grid power factor requirements. A failed NCP1654BD65R2G typically presents as the PSU coming up on auxiliary supply but failing to deliver stable main rail voltage under load.

SI8016HSP8 PWM Controller

The SI8016HSP8 high-voltage PWM controller (SOP-8) drives the primary flyback stage. The same controller is also used in the APW9 and APW9+ PSUs — failures present as no switching activity on the primary side. Verify the controller's VCC supply (from the auxiliary winding) before replacing.

Primary Switching MOSFETs

The APW8 uses a stack of 600V-class N-channel MOSFETs on the primary side. The TK62N60W (K62N60W) is the higher-current primary MOSFET; the K39N60W5 (TK39N60W5) is the mid-current device (38.8A); the TK20A60W5 handles a secondary primary-side stage (600V / 20A). Test in diode mode: a healthy MOSFET shows 0.3-0.6V drop between drain and source. A shorted primary MOSFET is the most common cause of a blown AC fuse.

Gate Driver (IX4424NTR)

The IX4424NTR dual low-side MOSFET driver provides the gate-drive signals to the primary switching MOSFETs. A failed gate driver leaves the PWM signal present but the MOSFETs un-driven — no switching action despite a healthy PWM controller. Same driver is used in APW7 and APW9 PSUs.

Output Rectification (SCS210AMC + TPHR8504PL)

The SCS210AMC (650V / 10A SiC diode, TO-220 through-hole) handles high-voltage secondary rectification. The TPHR8504PL (40V N-channel MOSFET) handles synchronous rectification on the main output stage with low conduction loss. The TPHR8504PL is shared across APW7, APW8, APW9, and APW12 — broad common stock.

Voltage Reference (ZTL431BFTA)

The ZTL431BFTA adjustable shunt voltage reference (2.5V / 100mA, SOT-23-3) sets the output regulation point through the feedback network. A degraded ZTL431BFTA causes the output voltage to drift out of spec — replace if the output is consistently high or low while the rest of the PSU is healthy.

Output Bulk Capacitor (1000µF 16V)

The 1000µF 16V aluminium electrolytic capacitor handles output filtering. A degraded cap (visually swollen top, leaked electrolyte, or measured high ESR) produces low rail voltage under transient load.

Schottky Protection (MBR0540)

The MBR0540 (0.5A / 40V Schottky, SOD-123) handles low-voltage signal-path protection.

Digital Supervision (PIC16F1704)

The PIC16F1704-I/SL microcontroller (8-bit, 7KB Flash, 14-pin) handles host I²C communication, fault code reporting, and basic supervision. Same PIC family used on Antminer hashboards and on the APW12 — common stock simplifies inventory. A failed PIC produces a PSU that runs healthy but cannot communicate with the control board (the miner reports "PSU not detected").

Small-Signal Transistors

The MMBT3906 (PNP, 40V / 200mA, SOT-23) and DSS5540X (PNP BJT, 40V / 4A, SOT-89) handle protection-circuit switching and gate-drive support. Failures usually produce subtle symptoms (current limit tripping early, protection mis-triggering) rather than dead PSU.

Magnetics & Inductors

The APW8 uses two transformers: PQ2620 for the main flyback stage and PQ5030T for the auxiliary supply. The JB1250W-L (1L2) and HS151025 are inductor / transformer support components. Magnetics failures are rare but visible — burned windings, cracked ferrite, or de-soldered pads. These components are not currently listed individually in the LYS catalogue; contact us for on-demand sourcing when needed.

Bitmain APW8 PSU Repair Components List

The table below lists every component LYS Shenzhen stocks for APW8 PSU repair. Each entry links directly to the corresponding part page — contact us at contact@lys-sz.com for the four unlinked components (JB1250W-L, PQ2620 transformer, HS151025, PQ5030T transformer) or for complete APW8 PSU replacement units.

The M6 Copper-Bar Bolt Check — Try This Before Opening the PSU

Like the APW12, the APW8 connects to the hashboards via M6 copper-bar bolts on the output side. The same mechanical failure mode applies: loose hashboard-side M6 bolts can present as a "dead PSU" complaint with PSU fan spinning and AC LED green, but 0V on the 16-20V busbars (or oscillating 0V↔output as protection latches). Always run the M6 re-torque check before opening the APW8 case.

1. Kill AC at the breaker / PDU. Wait 60 seconds for bulk caps to discharge.
2. Use a calibrated torque screwdriver in the 0.5-5 N-m range.
3. Loosen each M6 bolt 1/8 turn first (resets the metal contact pressure), then re-torque to 3.0 N-m (spec range 2.5-3.5 N-m).
4. Inspect lock washers (should be present per bolt), ring terminals (no cracked crimps or corrosion), bolt threads (clean, not stripped), and busbar contact surfaces (no blackening or bluing).
5. If contact surface is blackened: polish with a brass brush (not steel) to bright copper, wipe with 99% IPA, apply a thin film of no-ox conductive grease (Noalox or equivalent) before re-torquing.
6. Re-apply AC and verify the miner boots through its normal sequence.
7. Schedule a re-torque calendar reminder for 6-12 months out as preventive maintenance.

Internal APW8 Diagnostic Workflow (When M6 Re-Torque Doesn't Fix It)

If the M6 bolt re-torque check is clean and the rail still won't come up, you have a genuine APW8 internal failure. The Bitmain-documented APW8 repair workflow runs through 6 sequential steps. The diagnostic uses the V9-1.2 test jig + special power test card firmware for full validation, or the S15 control panel V1.2 as a substitute for the test jig. Without official tooling, a multimeter + electronic load can substitute for the function check.

Bench setup requirements

• AC controllable power supply / voltage regulator: output 200-250V, current limit 0-20A — for safe AC power-on inspection. If unavailable, a 100W ordinary light bulb in series with the AC line bus can be used as a current-limiter (with caution).
• Electronic load: 2KW capable, 0-50V voltage rating. If unavailable, a resistive load matched to the APW8 output spec can substitute.
• Multimeter: Fluke 15B+ recommended.
• V9-1.2 test jig + power test card firmware: for full I²C-based validation. The S15 control panel V1.2 is the supported substitute when the test jig is not available.
• Oscilloscope: optional but recommended for waveform analysis on the PWM and LLC stages.
• Soldering equipment: 80W+ constant-temperature soldering iron with tip head (300-350°C for chip resistors/capacitors) and blade head (380-420°C for plug-in components). Thermal chimney / hot-air station at 260°C ±2°C for chip removal — do not over-heat or the PCB will blister.
• Auxiliary materials: thermal silicone grease (model 2500) for MOSFET-to-heatsink interface, 704 silica gel for protective glue replacement on PCBA components, lead-free solder wire, flux, anhydrous alcohol for board cleaning.

Safety — mandatory before opening the case

The bulk capacitor must be discharged before any soldering operation. Verify the residual voltage with a multimeter — the cap must measure below 5V before you touch the board. Wear an anti-static wrist strap, work on a grounded anti-static workbench, and follow Bitmain's PSU enclosure opening procedure to avoid damaging internal components.

6-step diagnostic procedure

1. Step 1 — External visual inspection. Check whether the appearance is seriously damaged or deformed, and whether the DC fan and the AC socket are damaged. If externally damaged, fix the obvious issues first.
2. Step 2 — Apply AC 220V and check basic operation. Verify the fan rotates normally. Use the multimeter to check the J6 output terminal voltage = 12V (range 12.1-12.5V acceptable for measurement tolerance). This confirms the 12V auxiliary rail is healthy. If 0V at J6, the fault is in the auxiliary circuit (see Step 4).
3. Step 3 — Open the enclosure and inspect for sparking. After discharging the bulk capacitor below 5V, open the case. Look for sparking marks on components or solder side. Pay particular attention to R33 (47K) — this is the voltage-detection startup resistor and a common failure point. Use the multimeter to check: F1 fuse for open circuit; U2 rectifier bridge integrity; PFC MOS at Q4 and PFC diodes D5 / D6 / D7 for shorts; main switch MOSFETs Q6 / Q14 / Q15 / Q16 for shorts; output synchronous MOSFETs Q17 / Q18 / Q19 / Q20 for shorts. Any short = check and replace, paying attention to the surrounding circuit (especially small-signal transistors that may be damaged alongside).
4. Step 4 — Verify the auxiliary 12V circuit. Test U5 driver IC, T1 12V transformer, Q5 main switch MOS, and D11 for shorts or open circuit. Inspect the surrounding components for burn marks. Replace any damaged parts.
5. Step 5 — Verify the PFC, PWM and drive stages. If the F1 fuse path is normal and AC powers up the fan and produces 12V at J6: measure the PFC large capacitor C16 / C17 — should read 370-380V DC across. If absent, check U1 pin 7 VCC = 12V (replace U1 if damaged). If U1 VCC is healthy but the PFC bus is missing, check the PWM circuit ICs U9, U10, U11 for correct 12V VCC supply (replace any failed PWM IC), then verify the T4 drive transformer for damage.
6. Step 6 — Bench AC power-on test. Before final AC test, short J15 PIN 4-5 (EN to GND) on the PIC communication header. This is the "default voltage 16.32V test mode" — without the control board, EN-to-GND enables the main output at the default 16.32V. Caution: incorrect short connections may damage the PIC chip. Apply AC 220V and verify the main output. If the PIC chip is damaged or firmware is corrupted, the small test card needs to be used before re-burning the PIC.

Key test point voltages (verified against Bitmain reference)

• VBUS (PFC bus voltage): measured at TEST7 with TEST2 negative as reference, the multimeter should read 375-385V DC.
• VCC (12V supply): measured at TEST11 with TEST7 negative as reference, should read 12-13V.
• J6 auxiliary output: 12V (12.1-12.5V acceptable).
• U1 pin 7 VCC: 12V (powers the main control IC).
• U9 / U10 / U11 VCC: 12V (powers the PWM circuit).

Post-repair soak test (Bitmain-mandated)

After repair tests confirm the PSU is functional, run a minimum 2-hour soak test at 80% rated load (≥80A on the main rail) before considering the unit cleared for customer use. This catches latent failures that survive the initial bench test but fail under sustained thermal stress.

When Chip-Level Repair Makes More Sense Than Replacement

New APW8 PSU stock is increasingly constrained — Bitmain has not manufactured this PSU generation at volume for several years. For S15 / T15 fleet operators, component-level repair is often the only realistic path. A small inventory of the primary MOSFETs (TK62N60W, K39N60W5, TK20A60W5), the secondary TPHR8504PL, the NCP1654BD65R2G PFC controller, the SI8016HSP8 PWM controller, the IX4424NTR gate driver, the SCS210AMC SiC diode, and the PIC16F1704 microcontroller covers the majority of bench-repair scenarios. The PIC16F1704, TPHR8504PL, and IX4424NTR are shared across multiple Bitmain PSU generations — a single stock covers APW7 / APW8 / APW9 / APW9+ / APW12 repair needs.

Stop DIY when there is visible cascade damage — scorched primary MOSFETs, blown PFC controller, multiple swollen capacitor tops, or burn marks on the silkscreen. Replacing only the visibly-broken part leaves adjacent damaged-but-not-yet-failed silicon vulnerable to the next event.

FAQ — Bitmain APW8 PSU Repair

Which Antminer models use the APW8 PSU?

The APW8 is the PSU for the Antminer S15 (28T / 27T / 26T) and T15 (23T) generation, with a 16-20V DC output range. Newer S17-class miners use the APW9 / APW9+ (14.5-21V); newer S19-class miners use the APW12 (12-15V). The APW8 is not directly interchangeable with newer PSU generations because the output voltage range and the connector pinout are PSU-generation-specific.

My APW8 shows AC LED green and fan spinning but the miner won't boot. Is the PSU dead?

Often this is loose M6 copper-bar bolts on the hashboard-side output, not a dead PSU. Run the M6 bolt re-torque procedure to 3.0 N-m (spec range 2.5-3.5 N-m) before opening the PSU case. The same mechanical failure mode affects all Bitmain APW-class PSUs because they use identical M6 copper-bar output topology.

What topology does the APW8 use?

The APW8 is a PFC-fronted flyback switching supply. The PFC stage is driven by the NCP1654BD65R2G (65 kHz fixed-frequency PFC controller). The main flyback PWM is driven by the SI8016HSP8 (the same controller is used on APW9 / APW9+). The output uses synchronous rectification via the TPHR8504PL MOSFET and a SiC SCS210AMC diode.

Can I use APW8 components on an APW9 or APW12 PSU?

Several components are shared across Bitmain PSU generations: the SI8016HSP8 (APW8 / APW9 / APW9+), the IX4424NTR gate driver (APW7 / APW8 / APW9), the TPHR8504PL synchronous rectification MOSFET (APW7 / APW8 / APW9 / APW12), the PIC16F1704 microcontroller (all Bitmain PSUs), the K39N60W5 primary MOSFET (APW3 / APW8), and the MBR0540 / MMBT3906 / DSS5540X small-signal devices. The transformers (PQ2620, PQ5030T), the PFC controller (NCP1654BD65R2G — APW8-specific), and the higher-current primary MOSFETs are generation-specific.

How do I test the APW8 after repair?

Connect the repaired APW8 to the Antminer communication test fixture via the I²C interface (same fixture as APW12). The fixture runs 4 automated test steps; "OK" on all 4 confirms successful repair. Without the official test fixture, an electronic load in CC mode (or a known-good S15 / T15 miner chassis) plus a multimeter for output voltage / ripple verification can substitute.

Sourcing APW8 PSU Repair Parts

LYS Shenzhen stocks 14 of the 18 critical APW8 components in our public catalogue. For the four magnetics components (JB1250W-L, PQ2620 main transformer, HS151025 inductor, PQ5030T auxiliary transformer), for complete APW8 PSU replacement units, or for bulk farm-scale orders, contact our team at contact@lys-sz.com — we operate an on-demand sourcing channel for repair components across the full Antminer PSU lineup including APW7, APW8, APW9, APW9+, APW11, APW12, and the newer APW17 series.

Worldwide shipping from our Shenzhen warehouse via DHL, FedEx, UPS, and sea freight. DDP shipping available for US and EU customers; case-by-case for other lanes — request a quote with your shipping country for confirmation.