Chip Domain Bypass

Chip domain bypass is a salvage technique that electrically jumpers around a failed voltage domain so the remaining domains on a hashboard can keep hashing. On Antminer boards, chips are grouped into voltage domains — clusters of chips sharing a regulated rail — and the domains are stacked in series across the board's supply, with the communication chain threading through every chip in order. That series architecture is efficient, but it has a brutal failure property: one dead domain breaks the chain for the entire board. Bypassing the bad domain restores continuity so the surviving chips can work again — at a permanent cost in hashrate.

Why the architecture forces the choice

Domain counts vary by generation — an S9 board divides 63 chips into 21 domains of three; an S17-class board runs 48 chips in 12 domains of four — but the topology is the same: power flows through the domains in series, and each chip's command input feeds from the previous chip's output down the chain. A shorted chip, a failed LDO regulator, or a dead domain rail therefore doesn't just cost you those chips; it opens the circuit for everything downstream, and the kernel log reports a truncated chip count or a zero-chip board. When the faulty domain cannot be economically repaired — no donor chips, underfilled packages, damaged pads — bypassing it is the remaining move.

What the procedure involves

Bench education, not a tutorial — but the shape of the work is this. First, the failing domain must be positively identified, typically on a test fixture with voltage measurements across each domain rail; bypassing the wrong domain wastes good chips and fixes nothing. The repair then bridges the domain at two levels: the power path, shorting the domain's input rail to its output so the series stack completes around the dead section, and the signal path, bridging the communication lines — the last good chip's clock and command outputs connected to the first chip after the gap, with reset and response lines bridged likewise. Finally, firmware expectations may need attention: the board now genuinely has fewer active chips, and depending on model and firmware, the EEPROM's stored configuration may need updating to match before the board is accepted.

The honest trade-offs

Bypass is a compromise, not a cure, and it should be sold to yourself that way. The board permanently loses the bypassed chips' hashrate. More subtly, removing a domain from the series stack changes the voltage arithmetic: the same supply now divides across fewer domains, shifting each remaining domain's share upward unless the supply point is compensated — which stresses surviving chips and can shorten their lives if ignored. A sloppy jumper adds resistance and heat exactly where you don't want it. And a bypassed board is harder to diagnose next time, because its baseline is no longer stock. The legitimate use case is keeping a partially damaged board earning when replacement chips or a clean repair aren't available — a triage decision, made deliberately, after the fault is confirmed to be confined to one domain. Document what you did — which domain, where the jumpers landed, what the post-repair chip count reads — because the next technician (possibly you, a year from now) will otherwise chase a "fault" that is actually your fix. And a bypassed board's resale value should reflect its reduced hashrate honestly; representing one as fully functional is how trust dies in the used-hardware market. If you would rather have the board properly repaired than permanently diminished, that assessment is exactly what our repair service is for.