Chain find 0 asic
The control board can't talk to any ASIC on that chain, so firmware powers the board off - you lose ~1/3 hashrate. Almost always a hardware/communication fault (cable/power), not config. Real log: 'check_asic_number: Chain 1 only find 0 asic, will power off hash board 1'.
→ Most 0-ASIC faults are a loose ribbon or power cable - reseating fixes them. A persistent 0 after cabling checks means a bad board to swap.
Low chip count
A board is hashing with fewer chips than nominal. A dead chip takes its whole DOMAIN, so losses come in contiguous domain-sized chunks. Scattered vs contiguous tells you chip-vs-domain.
→ Rule out thermal + PSU + tuning first. A stable shortfall that hurts output is a board-swap/RMA item.
ERROR_FAN_LOST
Firmware saw a fan at 0 RPM or outside its allowed range (normal ~3,000-6,000; min ~1,000-2,000) and stopped mining to protect the boards. A broken tach wire reports 'no fan' even while the blade spins.
→ Fans are cheap and quick - a bad fan or loose connector is the usual cause and the fix.
over max temp
A board exceeded its limit and throttled or shut down to save the chips (typical shutdown ~90 °C chip / ~80 °C PCB). Cause is airflow, ambient, dust, or a bad sensor - usually NOT the board. Real log: 'over max temp, pcb temp 85 chip temp 110'.
→ Fix the cooling path (airflow, dust, fans, ambient). If a sensor is lying, the board may need swapping.
No hashboard found
A board isn't enumerated. One missing = that chain is dead or unpowered. ALL missing = suspect power delivery or the control board.
→ Reseat → isolate ribbon vs board → if isolated to the board, swap/RMA it. All-boards-gone with good power points at firmware or the CB.
Low / unstable hashrate
The miner mines below its rating. Diagnose by PER-CHAIN behavior: one board low = that board; all boards down evenly = system-wide (thermal, PSU, or firmware). Unstable/spiky = network/pool.
→ Split low-and-steady (hardware/thermal/PSU) from unstable (network/pool). Treat the root cause, not the frequency number.
No web UI / no IP
You can't reach the miner. It has no link, didn't get an IP, its IP changed, or the CB isn't responding.
→ Usually a cable/switch/DHCP issue found with the IP-report button. Persistent no-boot is a control-board problem.
Pool dead / rejects
One pool Dead with backups Alive = that endpoint/URL is wrong. ALL pools dead = the miner's NETWORK path (internet/DNS), not three pools failing at once. Stale submissions involve outdated jobs; inspect the pool reject reason before attributing any rejection to computation or network faults.
→ Verify account/worker configuration and network, then classify reject reasons before choosing the diagnostic branch.
