note from assembling a T12 soldering iron clone kit
in my kit, the front panel PCB was not parallel with the front panel:
inserting a 1mm or 2mm thick washer between the rotary encoder and the front panel fixes this:
the provided wires and heat shrink didn't seem adequate. use 20awg or thicker wires. also, ground the chassis:
there isn't any provided way of stopping the PSU board from sliding into the back of the front panel PCB.
however, there's a screw hole next to
C13 on the PSU board.
drill a hole in the chassis below the board's screw hole and use a self-tapping screw to secure the PSU:
this diagram from Banggood shows how to wire the handle. be sure to solder in the vibration switch the correct way:
it's easier to solder the handle cable to the surface pads on the handle PCB:
it looks like loading a tip into the handle causes the PCB to bend quite a bit. the handle may be the first part that breaks:
when attaching the top half of the case, the front panel power connector was higher than the top of the enclosure would allow. if this happens, bypass the connector by soldering directly to its pins: