Rebuild
A rebuild is an asic restored in a workshop: chips or boards replaced, everything cleaned, tested under load. The maker warranty on it is already gone.
What a rebuild is
The work usually goes like this: diagnostics along the chains, replacement of dead chips or of a whole hashboard, ultrasonic washing of the board, fresh thermal paste, new fans where they are due, a run under load. A good rebuild ends with several hours of running at even temperatures rather than with a power up.
What was actually done matters more than the word rebuild in a listing. Replacing one board and resoldering forty chips are different stories, and the price has to tell them apart. Ask for a list of the work rather than a blanket claim that the asic was restored.
A rebuild kills the maker warranty: an opened case and the marks of a soldering iron show at once. In exchange a decent workshop gives you its own, usually a short one. No warranty at all is not a discount; it is the risk moved onto you.
A restored asic does not become new in terms of remaining life. The rest of the parts go on aging, so payback gets worked out from the purchase price and from your own rate rather than from the spec sheet figures of the model.
Quick reference table
| What gets done | chips or a board replaced, washing, paste, a run under load |
| Maker warranty | gone |
| Workshop warranty | usually short, ask about it directly |
| What to ask the seller for | a list of the work rather than the word restored |
| How to work out payback | on your own price and your own rate |
How to look a rebuild over
A run under load of no less than an hour, with the case warmed through. On a cold asic half the problems stay invisible.
The spread of temperatures across the chips within each board. An even chart beats a low average: a step in it gives away a badly seated heatsink or fresh solder.
The count of live chains and hashrate against the spec sheet. A rebuild with two boards out of three does get bought, at a different price.
What the board was washed with and how. Traces of flux and white streaks under the heatsinks are future corrosion rather than a cosmetic matter.
An example from the bench
An asic comes in a third of its hashrate down. The log shows that one board does not answer at all. We swap the board, wash the others, put on fresh paste and run it overnight. In the morning the hashrate is at spec, temperatures are even, and that is something you can sell as a rebuild.
Related terms
Where to go next on the site
Hardware
- ASIC Miner knowledge base
- ASIC Chip and Hashboard knowledge base
Guides
- ASIC Manufacturers knowledge base
Numbers
Questions and answers
Is a rebuild worth buying
It is, if the work is named and there is at least a short workshop warranty. Silence about what was done is the main warning sign.
How long does a restored asic last
Nobody will give you an honest figure: the rest of the parts were aging all that time. So the price gets worked out so that payback does not depend on a long life.
How does a rebuild differ from a plain repair
A repair brings the asic back to working order, while a rebuild prepares the whole asic for sale: washing, paste, fans, a run under load.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .