Hi-Tek Series 725 fourth generation
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Hi-Tek Corporation, a division of NMB, produced its 4th generation of PC compatible keyboards between 1990 and 1998. The 4th generation introduced a flatter case profile.
Contents
Description
The external appearance of the 4th generation keyboards is flatter than the 3rd generation and is similar to the popular Cherry G8x series of keyboards. The main body of the case is rectangular plank with a wedge extension that places the front face of the keyboard at a slight angle. The front edge of the upper case shell is beveled slightly to provide a more comfortable hand position when resting. A switch accessible through an opening in the rear cover allows the selection from either XT or AT protocols on some models. 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.
Top view
Front left view
Right rear view
Rear view
Lock status led panel
Bottom view
AT/XT protocol switch
Elevation foot collapsed
Elevation foot extended
Rubber non-slip pad
Construction
4th 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
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 seven un-threaded screw bosses used to secure the lower case shell to the upper case shell using self-tapping screws. Three openings are molded into the shell to allow the status leds to show through the status panel. The shell is embossed mold date and mold number.
Interior of upper case shell
Upper case shell status led openings
Upper case shell mold date and number
Lower case shell
The lower case shell is molded from the same plastic as the upper case shell. The lower case shell incorporates six un-threaded screw bosses used to secure the switch assembly to the lower case shell using self-tapping screws. Interestingly, most examples only use one screw. The cable opening is shaped to engage and molded portion of the cable to provide retention and strain relief. 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 shell has an embossed mold date and mold number. A set of four tabs are used in some examples to retain a small controller PCB.
Lower case shell
Lower case shell cable opening
Lower case shell cable showing retention
Lower case shell board retention tabs
Labels
All 4th generation keyboards have an identification label that lists FCCID, country of origin, manufacturer name and address, certifications, part number, and revision. 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
4th generation keyboards came with a variety of cables. Early examples have thick coiled cables with 5 pin DIN connectors similar to those of 3rd generation keyboards. Some have a thinner coiled cable with either a 5 pin DIN connector or 6 pin mini DIN PS/2 connector. Later keyboard come with a straight cable with either a 5 pin DIN connector or 6 pin mini DIN PS/2 connector.
Switch assembly
The switch assembly consists of one or two PCBs, 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 switches are Series 725. Two different PCB configurations are known to exist. Most examples have a single PCB with no anti-ghosting diodes. Some early models have a second small PCB which contains the controller and clips into a set of four retention tabs in the lower case shell. The main PCB on these examples has anti-ghosting diodes and supports N-key rollover.
Keycaps
The keycaps are made of PBT with high quality dye-sublimated legends. They have cylindrical tops and sculpted profile. The legends on later examples is thinner than early examples. Some examples have the stepped keycaps found on all 3rd generation boards.
Known part numbers
| Part Number | Rev | Model | Date | Main Switch | Spacebar Switch | LED Switch | Cable | FCCID | Branding | Reference |
|---|---|---|---|---|---|---|---|---|---|---|
| 118413-002 | RT 101+INTEL | 05-92 | Grey 2-Eye Tactile | Grey 2-Eye Tactile | Grey 2-Eye Tactile | Beige coiled with PS/2 connector | AQ65RT101-LC | None | ||
| 116300-004 | RT-102 IT | 04-90 | Black 2-Eye Tactile | Neon Green 2-Eye Tactile | Black 2-Eye Tactile | Beige coiled with AT connector | AQ659ZRT-725M | None | ||
| Hi-Tek 120016-201 REV.B | RT-8255C+ | 06-95 | Black 2-Eye Clicky | Blue 2-Eye Spacebar Clicky | No Integrated LED | Beige coiled with AT connector | AQ6-OAKZ15 | None |
