Se Jin M-8700

Se Jin M-8700
Switch	Futaba MA
Sense method	Metal contact Conductive membrane assembly
Protocol	AT / XT
Keycaps	Double-Shot ABS Dye-sub PBT

The Se jin M-8700 was a series of AT layout keyboards manufactured by Se jin Electron and OEMed for various computer manufacturers and brands.

The M-8700 could come with ABS doubleshot or dye-sub PBT keycaps, and Futaba MA Inverse cross mount clicky switches or a currently undocumented Futaba mount membrane switch.¹⁾

There are multiple variants of the M-8700:
'M7USxxx-xx' The US-English variant of the M-8700.
Currently documented with Futaba MA switches and ABS doubleshot keycaps.
Brands documented to have used this model include Vendex Headstart²⁾, VTI,³⁾ Apex by Epson,⁴⁾ Samsung⁵⁾ and Packard Bell.
Despite having a cutout for a lock‑light switch, no US model is currently documented as having used one; they are instead locked into a single protocol.

'M7Kxxxx-xx' The Hangul variant of the M-8700.
Currently documented to with Futaba MA or an undocumented membrane switch.
This version has been documented to use ABS doubleshot or dye-sub PBT keycaps.
Brands documented to have used this model include Samsung⁶⁾ and Daewoo⁷⁾.

'M7US0SX-37' A unique Vendex Headstart branded version of the M-8700 with a completely different case design and auto AT/XT functionality.
Documented with Futaba MA switches and ABS doubleshot keycaps. ⁸⁾

'Headstart Explorer' An M-8700 assembly integrated directly into the Headstart Explorer computer. ⁹⁾
Currently not much is documented about this variant, other than that the documented versions use the membrane switch.

The M-8700 has been documented with three different kinds of cases:

A generic version used in most rebrands and all unbranded models:

The top is made of ABS plastic
Externally, it has a pen holder above the top key row and a lock-light sticker on its top right; on rebranded models it features a badge cutout in the top-left.
Internally, it has date of manufacture time stamps and plastic standoffs for fastening the bottom case to the top case.

The bottom is made of ABS plastic
Externally, it has a cutout for an AT/XT switch, a keyboard sticker documenting the keyboard's FCC ID, country of origin, model number and serial number and four feet in total: two non‑slip feet and two flip‑out feet with two settings per foot (one sets the keyboard at 11°; the other at 15°)
Internally, it has 4 pegs for holding the assembly in place, a metal RF shield and two rubber pads for preventing the assembly from shorting on the RF shield.

The assembly on the Futaba version consists of a PCB and a switch steel plate.
The PCB has a sticker which documents the assembly's model and serial numbers.

A 'M7US0SX-37' version produced for Vendex Headstart:

The top case is made of ABS plastic
Externally, it features a sloped design near its top with the Vendex Headstart logo in it's top-left corner, and a distinctive lock-light sticker with a slant on it's left side in it's top-right corner.

The bottom case is made of ABS plastic
Externally, it has six screws that fasten the two case pieces together and four feet in total: two non‑slip feet and two flip‑out feet that use the same design as the M‑8700 on a large protrusion at the back of the case.
It has two stickers on the back: an auto AT/XT sticker and a keyboard sticker with the keyboard's FCC ID, country of origin, model number and serial number documented on the back.

As of writing, no internal pictures are documented; however, based on the documented example, it appears to use a painted steel plate.

A 'Headstart Explorer' version used in the Vendex Headstart Explorer computer.

The top case is made of ABS plastic
Externally, it has three screws, one at the top and one on each respective side for fastening the top into the bottom; lock-lights cutouts with lettering embossed directly into the case and two large plastic hinges for flipping the keyboard up onto the top of the computer case when not in use.

The bottom is made of ABS plastic
Externally, it features only a 'Headstart Explorer' logo printed in its bottom‑left corner.

As of writing, there are no documented internal pictures of the case.

The only documented picture of the assembly shows a steel switch plate, a mainboard with membrane connectors, and a cable for internal cable for connecting to the computer.

All versions of the M-8700 use OEM profiile Futaba inverse cross mount keycaps in either ABS doubleshot or dye-sub PBT.

Detailed pictures are from a model identical to the one doomsday_device pictured. The solder and flux are not original as the old Futaba MA switches were swapped with NOS ones.

Pretty pictures provided by @doomsday_device from the KBI discord.