The Bitmain APW8 is a slide-in power supply module that locks directly into the chassis of the Antminer DR5, S11, S15 and T15 rather than sitting as a separate brick. Detaching it is a two-part mechanical job: back off the retaining bracket that ties the PSU to the miner shell, then release a spring-loaded metal tab and slide the unit out. Done in order, on a fully de-energized miner, it takes a couple of minutes and no force. This guide covers the safe sequence, the tools, and how to confirm the reattachment before you power back up.
Before you start: why the sequence matters
On this generation the APW8 shares its housing with the miner and feeds the hashboards through low-voltage DC output connectors on each board — this is the pre-S17 wiring scheme, so there is no bolted copper bus-bar to unbolt, just the module lock and the DC leads. The two real hazards are both about respect, not fear:
- Never open the sealed PSU shell. The dangerous voltage lives on the mains side and the bulk capacitors inside the case, which can hold a lethal charge long after the cord is pulled. The outside of the module, and its low-voltage DC output (roughly 8–20 V depending on the model), is not a shock risk.
- The DC side is a current hazard, not a voltage hazard. A dead short across those low-voltage output pins won’t shock you, but it can dump enough current to arc, spot-weld a screwdriver, or vaporize metal. Pull AC first so the rails are dead before anything conductive goes near them.
Tools you’ll need
- A 3 mm hex driver for the retaining bracket screws.
- A pair of gloves for grip and to keep fingers off sharp chassis edges.
- A clean, stable, static-safe surface with room to lay the miner on its side.
- Optional: a multimeter to confirm the output rails are dead before and after the job.
Detaching the APW8 — step by step
- Power down and pull the AC cord. Stop the miner from the dashboard if it’s still running, switch off at the wall/PDU, then unplug the AC lead. Give it a minute for the internal capacitors to bleed down before you touch anything.
- Disconnect the DC output leads. Release each hashboard power connector by hand or with a gentle rock — never pull on the wires, always on the connector body. Note which lead went where; they are keyed but it saves guessing on reassembly.
- Set the miner PSU-side up on a stable surface. Lay it so the retaining bracket that clasps the PSU to the miner shell faces you.
- Remove the retaining bracket. Back out the bracket screws with the 3 mm hex driver and lift the metal holder off. Keep the screws in a dish — they are easy to lose and are the only thing making the module captive.
- Rotate the miner 90° counterclockwise to reach the release tab. On the side of the PSU you’ll see a spring-loaded metal tab that engages the chassis hooks (this is the tab shown in the manufacturer’s photo/video).
- Depress the tab and slide the PSU out. Press the tab in and, at the same time, push the module outward along its rails. It should release with light, even pressure. If it fights you, stop — the tab isn’t fully depressed or a lead is still attached. Do not pry.
Reattaching the APW8
- Line the module up with the chassis rails and hooks, leading with the AC-input end of the PSU.
- Slide it inward until the metal tab snaps home — you’ll feel and hear the lock seat. A module that isn’t fully seated will sit proud of the chassis; it should be flush.
- Refit the retaining bracket and tighten the screws snug, not gorilla-tight — you’re clamping sheet metal, not torquing a head bolt.
- Reconnect each DC output lead to its hashboard. Seat every connector fully; a half-seated power lead is a classic cause of one dead board or intermittent hashrate.
How to confirm it worked
- Mechanical check: the module is flush with the chassis, the bracket is on, and it doesn’t wiggle when you tug the housing (not the cables).
- Connector check: every DC lead is fully clicked in and routed clear of the fans.
- Power-on check: plug AC back in, power up, and watch for the PSU indicator and a normal boot. In the miner’s web UI, confirm every hashboard enumerates and reports voltage/temperature. A board that shows 0 chips or no temperature after this job almost always means an unseated output lead — power down and reseat, don’t run it that way.
- Let it run 15–20 minutes and confirm hashrate settles at the expected level with no board dropping out.
Common mistakes and field notes
- Pulling wires, not connectors. The DC leads are crimped; yanking the wire can back a pin out of the housing and create an intermittent connection.
- Feeding it from a 120 V circuit and expecting full output. The APW8, like the APW3/APW9 family, will run on 110/120 V, but it delivers its full rated output only on a 200–240 V feed, and a single 15 A/120 V circuit cannot supply a big miner’s full draw. Check the wattage on the miner’s label against your circuit before blaming the PSU for underperformance.
When to escalate
If the miner won’t power on with a known-good APW8, one hashboard stays dark after confirmed-good reseating, or the PSU shows no output on a meter, the fault is past a simple reattach. Bench the PSU against a known-good unit to isolate whether it’s the module or the board, and treat a PSU that trips, buzzes, or smells hot as scrap on the output side — never open it to “fix” it. For a structured walkthrough of isolating a dead board versus a dead supply, work the diagnostic tree rather than swapping parts blind.
Manufacturer reference: Bitmain’s own detach clip is here — youtu.be/_XaSQfoFJMo.
Related
Match a replacement or spare with our ASIC repair parts catalog, isolate a board-versus-PSU fault with the ASIC fault finder, pull the original documentation from our miner manuals library, or hand the unit to the bench and start a repair.
