The used ASIC market can offer very attractive $/TH pricing, but it is also one of the easiest places to buy hardware that looks profitable on paper and turns into a maintenance problem afterward.
Hashrate alone tells very little about the condition of a machine.
My basic checklist before buying a used ASIC would include:
- individual hashboard performance;
- chip error rate;
- temperature consistency between boards;
- PSU condition;
- fan RPM and bearing noise;
- signs of corrosion or moisture;
- dust contamination;
- repair history;
- previous overclocking;
- firmware currently installed;
- total runtime if reliable logs are available.
Another important point is where the miner was previously operated.
A machine that spent two years in a clean, temperature-controlled facility can be in better condition than a much newer unit that operated in a dusty environment with unstable power.
I would also be cautious with miners where one board produces noticeably lower hashrate than the others. Sometimes it is a simple repair, but sometimes it is the beginning of repeated board failures.
For people who regularly buy second-hand mining equipment:
What are the biggest red flags you look for before buying a used ASIC?
And would you buy remotely based only on logs and video testing, or insist on third-party inspection?
I would check hashboard stability, temperatures, repair history and how the miner performs under sustained load. A machine that looks fine for a few minutes can still have expensive hidden problems.
This checklist is really practical, especially the focus on sustained-load testing instead of just headline hashrate. I’d also insist on checking repair history and board temperature consistency, because those two can reveal problems that a short video test might easily miss.