Marquardt Series 6180
Manufacturer	Marquardt
Part Number	6180
Switch Type	Linear
Travel	4mm
Sense method	Metal contact
Mount	Plate mount
Keycap mount	Cherry MX-compatible
Rated lifetime	Unknown
Quoted operating force	Unknown

Marquardt Series 6180 is a DIN-compliant linear switch series manufactured by Marquardt. It consists of two variants. It is deeply related to Cherry MX Olympia Clear which appears to have been a custom order switch for Marquardt that is interchangeable with Series 6180.

Both switches in the series share the same general design, two-stage spring, bottom housing, including integrated diode, and contact module. They also share a similar method of action - i.e. that the stem makes contact with a separate part, which then puts pressure on the contact module. Housings are two-way incompatible between the switches in the series due to the actuator part sitting differently in the housing in each switch.

This is the earlier version of the switch, found in an Olympia Carrera dated 1986. It has a dark brown top housing, and a slightly mint green stem. The stem is MX mount, and slides past a semi-free-floating contoured plastic rocker (it merely rests in a recess in the top housing) with a peg on the other side. This peg is what puts pressure on the contact module, closing the circuit. The switch weighting is in the ballpark of MX Black, and has 4mm travel. When fully depressed, the stem is completely inside the housing.

This later version of the switch, found in a 1988-dated Carrera, has a completely black top housing and white stem. The stem remains MX mount, but is slightly taller than the brown variant and has a notch. Instead of a plastic rocker, it slides past a uniquely shaped leaf spring, which rests in a slit in the top housing. It has a prong which puts the pressure on the contact module. This switch is significantly heavier ¹⁾. It still has 4mm travel, but the stem is slightly outside of the housing at bottom out.