How to Remove the Power Supply from an All-in-One Mining Machine

An all-in-one mining machine carries its power supply inside the chassis, feeding the hashboards through solid copper busbars rather than external cables. Pulling that PSU is a common first step for a bench repair, a PSU swap, or diagnosing a dead unit — but two very different hazards live in that module. The busbar terminals carry over 200 amps in service: the low-voltage DC bars won’t shock you, but that much current will arc and vaporize metal if you let a bar short across a terminal or the chassis. The shock hazard is the mains and PFC bulk capacitors sealed inside the PSU shell, which hold a charge after shutdown — which is exactly why you never open that shell. Done in the wrong order the job can also damage the control board. This guide walks the removal in the correct sequence, with the safety checks the OEM instructions leave out.

Before you touch a screw: fully power down the machine, switch off the wall breaker or PDU, and physically unplug the AC cord(s). Then wait at least 60 seconds. Bitmain-class supplies (APW9/APW9+, APW12, APW17) hold residual charge in their bulk capacitors after the AC is cut; the delay lets the PFC caps bleed down so you are not working on a live, charged supply. Never open the PSU’s own metal shell — this procedure removes the whole sealed unit, not its lid.

Which machines this applies to

This covers integrated-PSU Antminer-style rigs where the power supply is a removable module inside the case and delivers power to the hashboards through copper busbars — the S17/T17 generation (APW9/APW9+), the S19 family (APW12), and the S21 family (APW17). The exact screw positions vary by model; the sequence — signal lines first, busbars next, mounting screws last — is the same across all of them. Always cross-check the teardown against the correct model repair manual before you start.

Tools you’ll need

• #2 Phillips screwdriver (magnetic tip preferred — dropped screws inside a chassis are a short waiting to happen)
• A 7–8 mm nut driver or socket for the copper busbar bolts (some models use hex-head bolts, not Phillips)
• ESD wrist strap tied to chassis ground
• Insulated gloves if you are servicing shortly after shutdown
• A small parts tray or magnetic mat — the busbar bolts and cover screws are not interchangeable
• A flashlight or headlamp to see connector latches

Removal procedure

1. Confirm the machine is fully de-energized. Miner off, breaker/PDU off, both AC cords unplugged, 60-second capacitor bleed-down elapsed. Clip your ESD strap to bare chassis metal.
2. Open the covers. Remove the Phillips screws securing the control-panel cover and the power-supply cover. On most units the control-panel cover releases by pressing and holding its knob/latch and lifting straight up; the PSU cover lifts vertically once its screws are out. Set the two covers aside — do not stack the screws together.
3. Disconnect the signal lines first — before the busbars. The PSU connects to the control board with low-current wiring: the secondary 12 V feed that powers the control board and fans, and the PSU communication/sense line (the I2C/PMBus and enable line the firmware uses to set voltage and read the PSU back). Depress each connector’s latch and pull by the plug body, never by the wires. Removing these before the copper bars means the control board is fully isolated when you loosen the high-current terminals.
4. Remove the copper busbar bolts. These flat copper bars are the main DC path — 12–21 V depending on model but at very high current (APW12 is rated to 233 A, APW17 to 267 A). Back out each busbar bolt fully and keep the bars from twisting against adjacent terminals as they come free. Keep the positive and negative bars from ever touching each other or the chassis — a stored charge across a shorted bar can arc and pit the copper. Note or photograph the polarity and stack order before you separate them so reassembly is unambiguous.
5. Remove the PSU mounting screws. With every electrical connection broken, remove the screws that fix the supply to the chassis rails. Confirm nothing else — no stray ground strap, no cable clamp — still tethers the unit before you move it.
6. Slide the supply out and support its weight. Slide the PSU along its rails to the end of travel, then lift it out. These supplies are heavy (an APW12/APW17 class unit is several kilograms). Support it with both hands as it clears the rails — dropping it can crack the board, bend the busbar tabs, or injure your hand. Set it on an anti-static surface.

How to confirm you did it right

• Both signal connectors and all busbar bolts are out — the PSU lifts free with zero resistance. If anything tugs, stop and find the missed fastener.
• No wire was pulled out of a crimp and no connector housing is cracked.
• The control-board side shows clean, undamaged connector headers and busbar landing pads (no scorching or discoloration — burnt busbar pads point to a prior over-current fault worth investigating).
• All fasteners are sorted by type so reassembly torque is correct — busbar bolts must be snug to avoid a high-resistance joint that will heat under load.

Common mistakes

• Pulling busbars before signal lines. Disconnect the signal connectors first, as in step 3.
• Skipping the capacitor bleed-down. “Unplugged” is not “discharged.” Give it the minute.
• Prying the PSU shell open. There are no user-serviceable parts inside a sealed APW; mains-voltage stages and charged caps are behind that lid. Swap the whole module.
• Yanking connectors by the wire. Release the latch and pull the housing, or you’ll back a pin out of a crimp.
• Reusing the wrong screw. Busbar bolts and cover screws are different lengths; a long screw in a shallow boss can bottom out on a trace.

When to escalate

If the busbar landing pads or PSU output tabs are scorched, if the supply is bulged or smells burnt, or if the machine tripped its breaker before you opened it, treat the fault as more than a clean swap — a failed PSU can take hashboard power domains with it. Diagnose the fault code first (the ASIC fault finder maps power and PSU errors), and if the supply is confirmed dead, source a replacement that matches the failed unit rather than a random substitute — APW12 hardware revisions differ, so match the exact model and revision.

Related

Grab the exact teardown for your unit from the per-model repair manuals, order a matched replacement or fresh busbar hardware from ASIC repair parts, and if you’d rather have the swap and post-repair validation handled on the bench, start a repair with D-Central.