Definition
Reflow is the controlled melting and re-solidifying of solder used to attach or reseat chips during hashboard repair. Rather than blasting a chip with heat, a technician guides the assembly through a temperature profile, distinct preheat, soak, reflow, and cooling stages, so the solder under a BGA chip melts evenly and re-forms clean joints. On a mining hashboard, reflow is used both to remove a failed ASIC and to set a replacement, and sometimes to re-melt suspect joints that have cracked from thermal cycling.
Why the profile matters
A good reflow profile ramps temperature gradually. Too cold and the solder balls never fully liquefy, leaving cold or partial joints; too hot or too fast and the thermal shock can crack ceramic capacitors, lift pads, or warp the PCB. Lead-free solder used on modern boards has a higher melting point than older leaded alloys, narrowing the safe window and making a calibrated rework station or programmable hot-air tool essential.
Where it fits in repair
Reflow is the heating step common to most chip-level work. It is part of removing a chip, part of placing a new one, and the final step after a chip has been reballed. Done correctly, it restores the hidden connections beneath a BGA package; done carelessly, it creates new faults around the rework site.
Reflow works hand in hand with related techniques. See BGA (Ball Grid Array) for the package that makes profiled reflow necessary, and Reballing for restoring solder balls to a chip before its final reflow.
In Simple Terms
Reflow is the controlled melting and re-solidifying of solder used to attach or reseat chips during hashboard repair. Rather than blasting a chip with heat,…