Buying a used ASIC miner: 12 checks before you pay

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Checks 1–2: price per TH and generation

1. Price per terahash, against new

Divide the asking price by the nameplate hashrate to get $/TH, and compare it with a new machine of the same model. The Gulf ASIC Price Index publishes weekly median $/TH by efficiency band from marketplace asks, completed sales and dealer quotes, and every ad on the Segments marketplace shows how its $/TH compares with its band. A used machine should be clearly cheaper per TH than new, since part of its life and warranty is gone. A price far below the median is a warning, not a bargain.

2. Model and generation (J/TH)

Efficiency, in joules per terahash, sets the power bill for every day the machine runs. Older generations are cheap to buy and expensive to run. Read the exact variant from the label and the status page, not from the ad: the same case can hold different hashboards.

Hashprice is what one terahash earns a day before pool fees; the closer a machine’s power cost per TH comes to it, the less is left for you.

Checks 3–5: proof it hashes, and how hard it worked

3. Real hashrate proof

On the Segments marketplace, used ads need a dated test video or status-page photos, and Hosted at Segments ads show each machine’s hashrate over the last 30 days from Segments’ own monitoring; the badge lapses if the machine goes offline.

4. Hashboard count and chip health

On the status page or kernel log, every hashboard (chain) should report the model’s full chip count and a hashrate in line with the others; a missing chain cuts output by about a third on a three-board machine. Watch for swapped boards: weaker or repaired hashboards inside a stronger model’s case. Marketplace sellers grade used machines A (all boards, 95%+ of nameplate, never repaired), B (all boards, 85–95%, minor repairs) or C (missing or repaired boards, or under 85%). Ask for the repair history; common Antminer faults explains each symptom.

5. Hours run, and where

Two years in a clean, cooled hall is not two years in a hot, dusty shed. Ask where and how long the machine ran, and look at photos of the heatsinks, fans and connectors: caked dust, rust or white corrosion point to heat, humidity or water damage.

Checks 6–8: power supply, firmware and serials

6. PSU match

Confirm the power supply is included and is the model the manufacturer specifies; a mismatched PSU can underpower the hashboards or fail early. Large hydro units often need three-phase power, so check what your site supplies.

7. Firmware: stock or custom

Custom firmware (Braiins, VNish, LuxOS and others) can tune power and hashrate, but some versions take a fee from the hashrate, and manufacturers may refuse warranty claims on machines that ran it. Ask what is installed, whether the machine was overclocked, and whether the seller will restore the manufacturer’s stock firmware before handover.

8. Serial number and ownership

Match the serial on the case label with the status page and the original invoice, and ask for proof of purchase. On the Segments marketplace, sellers give serial numbers to Segments staff, who check them against stolen and duplicate machines; they are not shown publicly.

Checks 9–11: warranty, cooling and delivery

9. Warranty status

Find out whether any manufacturer warranty remains and whether it transfers to you, and whether the seller covers a machine that arrives dead (dead-on-arrival, or DOA, cover). Marketplace ads show the warranty status and the seller’s DOA cover in days where the seller gives them.

10. Cooling type

A hydro-cooled miner only runs on hydro racks with a coolant loop; it cannot sit on a shelf with a fan. An air-cooled one needs strong airflow in the hottest month. Buy for the site you have; see hydro, air or immersion cooling.

11. Shipping, customs and who pays

Get the Incoterm in writing: ex-works (EXW) means you collect and pay for everything from the seller’s door; delivered duty paid (DDP) means the seller delivers with duty and taxes paid. Budget freight, insurance, clearance and import taxes, and agree who carries the transit risk. Machines already in Segments centres are sold in place, without shipping or downtime.

Check 12: where it will run, and what that costs

A used miner is only a good buy at the power price it will actually pay. At Segments in October 2026:

• Hosting: 6.8¢ per kWh all-in (power, cooling, monitoring, cleaning, maintenance), billed on kWh used, 12-month contract; 5.8¢ with installation paid up front, 7.8¢ with installation in the rate.
• Installation per kW: air-cooled $30, hydro $60; $45 and $90 when paid up front, nothing when it is in the rate.
• Transport to site: $150 per machine by default.

Marketplace ads estimate profit and payback at the electricity rate you choose; or use the profitability calculator and how to choose an ASIC.

What each check costs you if skipped

Buying through the Segments marketplace

• Every ad is reviewed by the Segments team before it goes live.
• Badges are issued only by Segments: ID verified, Verified Segments client and Verified dealer for the seller; Hosted at Segments and Segments-inspected (bench-tested by Segments staff) for the machine.
• A price check on every ad against its band median, and a Report this ad link.

Unless the Segments sales team handles the deal, the sale is agreed directly between buyer and seller, so never pay before the machine is verified. Segments never asks for payment to a personal wallet or bank account; Segments deals are paid against a Segments invoice by bank transfer. See safety on the marketplace.

Not sure about a machine? Ask for a bench test. Segments’ repair lab tests miners under full load for 12 hours, with photos and a test report; if it finds a fault, you get a diagnosis and a written quote before any repair.