Hi-Tek Series 725 third generation

From Deskthority Wiki
Jump to navigationJump to search
File:Template icon--Under construction.svg Page is under construction— This is a work in progress. Please contact Engicoder before editing for content other than grammar/spelling.

Hi-Tek Corporation, a division of NMB, produced its 3rd generation of PC compatible keyboards between 1986 and 1989. The 3rd generation introduced it's first 101 key layout based on that of the IBM Model M.

Description[edit | edit source]

The external appearance of the 3rd generation keyboards is modeled after the IBM Model M, mimicking its wedge profile and 101 key layout. A switch accessible through an opening in the rear cover allows the selection from either XT or AT protocols. A set of molded feet can be extended to elevate the back of the keyboard. When collapsed the feet are flush with the bottom surface. Four rubber pads prevent the keyboard from sliding on smooth surfaces.

Construction[edit | edit source]

3rd generation keyboards use the standard method of keyboard construction consisting of 4 major components, the upper case shell, the switch assembly, the lower case shell and the cable.

Upper case shell[edit | edit source]

The upper case shell is a single piece of beige, molded plastic with a surface texture created as part of the molding process. The upper case shell incorporates two un-threaded screw bosses used to secure the lower case shell to the upper case shell using self-tapping screws. A set of tabs in the upper case and matching openings in the rear cover provide the primary means of securing the two halves together. Some instances have an embossed mold date and mold number.

Lower case shell[edit | edit source]

The lower case shell is molded from the same plastic as the upper case shell. The lower case shell incorporates three un-threaded screw bosses used to secure the switch assembly to the ulowerper case shell using self-tapping screws. A set of four openings mate with tabs in the upper case shell to join the two halves together (described above). The lower case shell has an integral cable channel on the exterior that provides strain relief. The channel allows the cable to be routed out the left or right side. A circular, removable plug allows the pcb connector to pass through the shell. A second strain relief on the interior forms a loop of cable around the center screw boss. A pair of feet are separately molded and snap into recesses in the rear cover. The position feet lie flush with surface of the rear cover when retracted and lock into place when extended. The center section of the interior is painted black with conductive paint, presumably to prevent electro-magnetic interference (EMI). Some instances have an embossed mold date and mold number.

Labels[edit | edit source]

Most 3rd generation keyboards have an identification label that lists FCCID, country of origin, manufacturer name and address, certifications, and part number. The identification label has a box for serial number if a separate serial number label is not used. All NMB Hi-Tek keyboards were "MADE IN THAILAND". Up to 3 small, colored paper inspection stickers can be found near the upper left hand corner of the smooth label section on the exterior.

Cable[edit | edit source]

All 3rd generation keyboards have beige coiled cable with a molded DIN 5-180 connector on the PC end and a 6 pin header on the PCB end. The cable is 3 feet long when relaxed and can be extended to a maximum length of 8ft.

Switch assembly[edit | edit source]

The switch assembly consists of the PCB, switches, key caps and switch plate. The switch plate is constructed of stamped steel with a thin, black finish. The ends of the plate are bent to mount to the upper case using 1 screw per side. The pcb is double sided and incorporates anti-ghosting diodes. The switches are Series 725.

Switches[edit | edit source]

3rd generation keyboards introduced the first tactile and clicky Series 725 switches.

Keycaps[edit | edit source]

The keycaps are made of PBT with high quality dye-sublimated legends. They have cylindrical tops and sculpted profile. The Ctrl and Alt keys are stepped on both sides. The modifiers of the middle three rows have unusual, stepped outer edges. The legends of the Alt keys and the secondary SysReq legend on the PrintScrn key are green. The number pad has brownish-gold secondary legends.

Known part numbers[edit | edit source]

Part Number Rev Date Main Switch Spacebar Switch LED Switch Cable FCCID Branding Reference
115039-003 02-89 Black 2-Eye Clicky Black 2-Eye Clicky Black 2-Eye Clicky Beige AQ659ZRT-101A None
116071 04-89 Black 1-Eye Tactile Neon Green 2-Eye Linear Black 1-Eye Tactile Beige AQ659ZRT-101A None
Retrieved from "https://wiki.themk.org/index.php?title=Hi-Tek_Series_725_third_generation&oldid=50426"