Kohaku Mill -Max Hotswap Mod

Build Specifications

Board - Kohaku (by SingaKBD)PCBs2x Kohaku Soldered PCBs
Modification - Millmax 0305 Hotswap Sockets
Solder - Used 63/37 Kester Rosin Core Solder
Tools - soldering Station, Flux Pen, Tweezers

Project Walkthrough & Process

Preparation & Layout Inspection

Mapping the PCB: Inspected both Kohaku PCBs for trace layouts and verified switch footprints to ensure 0305 sockets would seat flush without interference from nearby components or stabilizers.

Cleaning: Wiped down the back of the PCBs with isopropyl alcohol (99%) to remove any manufacturing residue or oils for optimal solder adhesion.

Socket Installation

Switch Insertion: Inserted old/sacrificial switches into strategic corners of the layout to act as a jig, holding the Mill-Max sockets firmly and squarely in place against the solder pads.

Seating: Pressed each 0305 socket onto the switch pins, ensuring they were pushed completely flush against the PCB pad surface.

Soldering & Verification

Tack & Secure: Soldered one side of each socket first, re-checking alignment to make sure no sockets were sitting crooked.

Final Soldering: Applied a small, controlled amount of flux and solder to the second pad, creating a clean, shiny, concave fillet around each socket.

Testing: Ran a thorough key-press continuity test using VIA/QMK before installing the PCBs back into the cases to confirm 100% connectivity across all keys.