Bitmain Antminer T21 (233Th)

AsicProfit Support AsicProfit · 27. 10. 2026

It points to the power side: the control board could not read the supply voltage, and the miner restarts. Measure each phase under load, not just at idle, and check the PDU sockets and cable terminations, since loose pins at the back of the socket are a known cause. If all three phases are healthy, the power supply is the next suspect. A unit under warranty should go back to Bitmain or an authorised repair centre.

AsicProfit Support AsicProfit · 24. 10. 2026

Yes, the standard T21 ships for 380-415V three-phase input, which surprises many buyers because most Antminers in this class are single-phase. Owners confirm it needed electrical upgrades and three-phase PDUs. A few hobbyists run modified T21s on single-phase power supplies at reduced wattage, but that is a do-it-yourself conversion outside the warranty. Check your supply before you order.

AsicProfit Support AsicProfit · 18. 10. 2026

Not on the T21. An owner reported that its three-phase connector is not designed to be pulled under load, and if neutral breaks before the live pins it can damage the cable and power supply. Switch it off at the breaker first, then unplug. Frequent hard power cycling is also hard on solder joints, so fix the cause of any overheating rather than repeatedly cutting power.

AsicProfit Support AsicProfit · 15. 10. 2026

The T21 does 190 TH/s at 19 J/TH, while the air-cooled S21 does 200 TH/s at 17.5 J/TH. You pay less up front but more electricity per terahash, so the T21's margin shrinks faster when difficulty rises or the Bitcoin price falls. It also needs three-phase power. With cheap three-phase electricity it can make sense; otherwise compare both in the calculator on this page at your power price.

AsicProfit Support AsicProfit · 1. 10. 2026

It can be both. Owners report T21s struggling in hot containers, with corner chips running much hotter than the rest, and boards that lose chips after a restart. Check fans and intake temperature, reseat the hashboard and control board cables, and test boards one at a time. Repasting the heatsinks has helped several owners. Faulty PDU socket pins that drop a phase can also cause odd chip errors. Underclocking through the hottest months is a common workaround.

AsicProfit Support AsicProfit · 28. 9. 2026

It is listed at about 75 dB, which is not suitable for a living space. Nearly all of its roughly 3,610 W becomes heat, about 12,300 BTU per hour, so the room needs strong ventilation or ducting for the exhaust. The listed operating range is 5 to 45°C, but owners advise keeping intake air well below the top of that range for long life.