SLIM19: the quiet 120V single-board Bitcoin miner

Definition

WHAT IS A SLIM19

SLIM19noun

/slɪm ˌnaɪnˈtiːn/ : SLIM19ed; SLIM19ing

To recycle stock S19 extruded aluminum into a quiet 120V single-board rig: a printed insert, top cover, and intake, two 120mm fans, an APW3++ power supply, and a control board. Since v2, no Loki kit: LuxOS PSU Bypass does in firmware what the adapter board used to do in hardware.

Why

BUILT FOR THE PLEB AT HOME

A stock S19 is a 240V data-center appliance that screams like a leaf blower. SLIM19 keeps one board, swaps the deltas for case fans, and runs off the outlet you already have. The point is not max terahash. The point is quiet heat that stacks sats.

QUIET BY DESIGN

Two 120mm fans (Gelid GALE 3500 RPM or Noctua iPPC 3000) replace the stock screamers. It lives in the room with you, not in a shed you avoid.

120V FRIENDLY

The APW3++ runs happily on a normal North American outlet. No 240V circuit install, no electrician, no panel work.

HEAT THAT PAYS

A single S19 board at reduced power is a space heater with a payout address. Winter comfort, denominated in sats.

LOKI-FREE SINCE V2

The LuxOS 2026-02-11 release added native PSU Bypass. One less part to buy, one less wiring step, one less point of failure.

OPEN SOURCE

Every printed part is a free STL in the SatStackingPleb/Slim19 repo: insert, intake, top cover, locks, and variants. About 1 kg of filament prints the whole kit.

E-WASTE, RECYCLED

The donor is a gutted stock S19 chassis and a working hashboard from a dead miner. The extrusion gets a second life instead of a landfill.

Hardware

THE RIG, IN THE METAL

Three finished SLIM19 rigs standing side by side — **Production line.** Three finished SLIM19 rigs: printed intake, dual 120mm fans, recycled S19 extrusion.

Bare S19 hashboard with heatsinks — **The engine.** One S19-family hashboard, heatsinks and all.

SLIM19 printed kit with cables and hardware — **The kit.** Printed insert, intake frame, rails, hardware, power and data cables.

Kit parts laid out on the bench with finished rigs behind — **Bench day.** Kit laid out, finished rigs waiting in the back.

Finished 6AWG power cables with copper lugs — **Copper path.** 6AWG pure copper runs, proper lugs, heat shrink.

Printed SLIM19 insert test fit on the bench — **Printed insert.** Fresh off the bed, ready for test fit.

CAD render of the SLIM19 full insert with cable pass-throughs labeled — **Slim19-insert-FULL.stl.** Power cables through the big opening, 8-pin data through the small one.

CAD render of the Anderson plug insert variant — **Anderson variant.** Both insert styles ship with a powerpole cutout option.

Gelid GALE 120mm mining fan and printed intake frame — **Airflow.** Gelid GALE 3500 RPM. Do not buy the 6000 RPM version.

SLIM19 on a windowsill wearing sunglasses — **On the road.** The Nashville unit, hashing on hotel power like it owns the place.

Build

BILL OF MATERIALS

Everything below plus a printer and an afternoon. Print files live in the SatStackingPleb/Slim19 repo.

Item	Notes
Stock S19 chassis	Donor case, extruded aluminum, gutted to the bare extrusion
1x S19-family hashboard	The single board this rig runs
Control board	AMLogic or Xilinx/BeagleBone. AMLogic needs no adapter hardware anymore
APW3++ PSU	The 120V-friendly supply (or an equivalent 12V server PSU). The stock APW12 wants 240V
6AWG pure copper cables	PSU to hashboard power path. Short runs, clean lugs, correct polarity
8-pin hashboard data cable	Control board to hashboard
2x 120mm fans	Gelid GALE FN-GALE-01 3500 RPM (not the 6000 RPM version) or Noctua NF-F12 iPPC 3000 PWM (may need cable extenders)
~1 kg filament	Prints the full kit
Screws	4x 3mm (insert), stock PSU-grill fan screws (PSU), 2x small 3mm (cover lock), 3mm screws (intake)
Loki DIY kitRemoved in v2	Replaced by LuxOS PSU Bypass. Firmware now does what the adapter board did

ASSEMBLY, EIGHT STEPS

Gut the donor chassis. Strip the S19 to the bare extrusion. Keep the stock PSU-grill fan screws.
Print your parts. Insert (full or split), top cover, cover lock, intake for your fan choice, hashboard lock.
Seat the hashboard in the extrusion and fit the hashboard lock.
Mount the PSU. The APW3++ sits against the insert, secured with the four stock grill screws plus its own housing screws.
Slide the insert in and secure with 4x 3mm screws. Power cables through the large pass-through, data cable through the small one.
Wire it. PSU 12V to the hashboard lugs with the 6AWG pair. 8-pin data from control board to hashboard. Fan headers to the control board.
Fans and intake. Mount both fans to the printed intake, then bolt the intake to the chassis.
Top cover on. Slide it from the front and lock it with the two small screws. Done: plug it into the wall.

Firmware

LUXOS SETUP, LOKI-FREE

Install LuxOS with Commander (docs.luxor.tech), then flip one setting that replaced an entire adapter board: PSU Bypass tells the firmware to hash with a supply it does not recognize, like your APW3++.

ENABLE PSU BYPASS

UI path: Settings > Advanced Settings > PSU Control. Set PSU Bypass to True and Bypass Voltage to your PSU's real output (the APW3++ delivers about 12.35V; measure at the lugs and use your number). Or via the API:

# port 4028, session_id from `logon` first
echo '{"command": "psuset", "parameter":"<session_id>,bypass_enabled=true,bypass_voltage=12.35"}' \
  | nc <MINER_IP> 4028 | jq

# verify after reboot: PSUBYPASS block shows "BypassEnabled": true
echo '{"command": "psuget"}' | nc <MINER_IP> 4028 | jq

Two gotchas, straight from the Luxor docs

bypass_enabled only takes effect after a reboot.
The setting persists only if autosave is on. With autosave disabled it is lost on reboot.
With bypass on, dashboard wattage is an estimate from the static voltage. Check the wall meter once and note the offset.

POINT IT AT A POOL, THEN TUNE

Create your pool subaccount before hashing (for Luxor: stratum+tcp://btc.global.luxor.tech:700, worker Subaccount.WorkerName). Then enable the Autotuner and set an ATM Max Profile, leaving Min Profile undefined so the board can underclock as far as it needs to stay cool. On a single board with two 120mm fans, let ATM do the work. Quiet, 120V-safe, and warm: that is the whole build.

FAQ

QUESTIONS, ANSWERED

Do I still need the Loki kit?

No. If you are on LuxOS 2026-02-11 or newer, native PSU Bypass replaces the Loki adapter entirely. On older firmware, update first or follow the v1 instructions.

How much hashrate should I expect?

One board at reduced power, tuned by the LuxOS Autotuner for the lowest watts at your target frequency. This build optimizes for quiet heat on a 120V circuit, not leaderboard terahash. Treat the sats as a rebate on your heating bill.

How loud is it really?

The stock S19 deltas are the loud part, and they are gone. Two 3500 RPM case fans on one underclocked board is closer to desktop PC under load than to a stock miner. ATM will throttle the board before it ever needs jet-engine airflow.

Where do I get a chassis and a hashboard?

Dead S19s are everywhere: repair shops, mining forums, auction lots. You need one working board and any intact extrusion. Repair vendors like Zeus Mining and D-Central sell tested boards if you want to skip the lottery.

Can I run it off solar?

The rig itself just wants clean 12V behind the APW3++. For Victron-native DC solar mining control, watch SatStackingPleb/venus-hashctrl: same ecosystem, built for exactly that.

SLIM19