Tai-Hao TH-5539

Tai-Hao TH-5539
FCC ID	GOG3YLTH-5539
Manufacturer	Tai-Hao
Layouts	Focus layout, ISO, 101-key ISO-like
Keyswitches	Alps SKCM Blue; Tai-Hao Aruz; Tai-Hao APC series
Interface	XT/AT switchable

TH-5539 refers to a variety of keyboards manufactured by Tai-Hao, using a number of different cases and switches, and sharing a single model number and FCC ID. The specific variant designations given on this page were provided by Tai-Hao, and may not be completely accurate considering how much time has passed since the keyboards were manufactured. Many such examples carry the Fame badge, a name used by Tai-Hao before APC and Clicker.

All examples found so far use a DIN 5 connector and are XT/AT switchable.

The Tai-Hao brochure below refers to the keyboards as "APC-n", e.g. "APC-8". Tai-Hao expanded "APC-8" as "APC switch, TH5539-8" and "APC-3" as "APC switch, TH5539-3".^[1]

Unknown variant

The specific model number of this variant is not known. The case style is reminiscent of the Chicony KB-5161 and both may have been inspired by the Alps Bigfoot series. It uses Alps SKCM Blue switches, suggesting that this was one of the older designs of TH-5539 keyboard, before Tai-Hao started using their own switches. The keycaps are pad printed. The PCB accepts both Alps and Cherry MX switches, similar to the NTC KB-6151N. Due to the "102" marking additional switch positions on the PCB, an ISO version may have existed.

Top
Bottom
Alps SKCM Blue switches
Restored and showing blue Alps switches - plate repainted
Backside - metal bottom panel restored and repainted
Early model PCB detail showing "102" designation and compatibility with Cherry MX and Alps SKCL/SKCM
Rear label

TH-5539-1

Confirmed only as "APC-1". This is a flat, minimalist design with no margin above the function keys for a legend strip. The shape is very similar to TH-5539-3, without any adornments, and with the status LED panel lined up with the function keys as there is no recess for a badge. This can be seen in the Tai-Hao brochure. In the 1992 example below, the switches are APC-branded, and the PCB is marked "APC-3A", indicating that APC-3 and APC-1 share the same PCB.

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Side
Bottom
Keycap detail
Keycaps, underside detail
Enter keycap
Internals with some keycaps fitted
Internals
PCB, bottom
Various details; the controller IC is dated 9240 (week 40, 1992)
Switch disassembly

TH-5539-2

TH-5539-2 features a gentle bowl profile, with the whole keyboard curving up gently towards the sides to complement the sculptured keycap profile. The keyboard has been found with Alps SKCM Blue switches and TH series doubleshot keycaps.

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Bottom
Rear label
Rear, showing the curve shape of the case and key plane
Top, showing switches
Blue Alps switches and keycap detail
XT/AT switch

TH-5539-3

TH-5539-3 is one of the better-known models. The design is quite similar to the more common TH-5539-5; TH-5539-3 has a narrower border, and the keycap skirts have round corners instead of the square corners of those of TH-5539-5. There is also a thin groove around the edge, and it lacks the central dip of TH-5539-5.

The images below show APC switches and laser marked TI series keycaps. It was also sold with Alps SKCM White switches^{[Citation needed]} and with doubleshot TI series keycaps.^[2]

Top
Bottom
LED cluster and patent number
Rear label
Top, showing switches
APC series switches

TH-5539-5

TH-5539-5 is the most common TH-5539 model, typically found with Tai-Hao Aruz switches and doubleshot keycaps. The enter key uses an Alps SKCM White switch;^[3] in one instance this has been found to be a circa 1989 or 1990 switch,^[4] in a keyboard from 1989.^[5]

The case dips down in the middle of the alphanumeric cluster. Aruz examples have TH series keycaps, but a different version also exists with TI series keycaps and coloured modifier legends.^[6] The switches in the referenced example are cited to be a 'white ALPS "complicated" clone'; the pictures show a switch with long side tabs, which may be the rare unbranded Alps SKCM White. The switches do not appear to be APC series.

Tai-Hao's example

This example uses doubleshot TH series keycaps; the Arabic legends are silkscreen printed.

Top
Bottom
Rear label
Top, showing switches
Aruz switches

Additional example

This example uses doubleshot TH series keycaps.

Product leaflet with model number; the dip in the upper case is clearly visible
Rear panel detail
Rear label
Aruz switch

TH-5539-8

TH-5539-8 relocates the status LEDs to the space above Insert/Home/Page Up. The status indicator space is instead used to hold a pad of sticky notes. A flip-up function key legend holder is placed above the function keys. The switches are APC series and the keycaps are double-shot and appear to be TI series.

Brochure image
Top View
Front side of F key labels
Back side of the F key labels
APC switch and underside of double-shot keycap
AT/XT Switch
Switches mounted in plastic plate
PCB Underside

TH-5539-9

TH-5539-9 has an IBM Enhanced Keyboard-style case, and has been found with blue Alps switches. The keycaps are a different series; they are ABS and are likely to be silk-screen printed. This may be the last keyboard model made with this keycap series.^[7]