The Unitron and I
I have always found Unitron to be a fascinating company. It's history, full of ambiguity, it's various origins, it's bizarre documentation, and an admirable determination to cloning another company's products. I have been closely interested in Unitron, as they played a contributing factor that enabled me to develop such an interest in electronic engineering.

It all began back in primary school (that's elementary school for some), when I first saw that first Apple, as many of us did. Sporting its mind-boggling game of 'Little Brickout', and testing my potential financial prowess with 'Lemonade Stand', this thing got my attention. Whenever the time came that we were allowed to play on the fond Apple, I would always be there. As time went on, and high school approached, Apple IIs began popping up everywhere. All the local schools had them, the Library had them, and even one of my father's good mates had one. But it didn't take long, researching pristine new Apples at my local Apple shop, to get an understanding of the concept of what a lot of money really was, and maybe more depressingly, what the term "totally out of reach" actually meant. Apples were prohibitively expensive, more money than my paper run would ever pay for in 100 years, and in 1981, there was no such thing as a "second hand" Apple.

But then an unexpected breakthrough; one of my mate's mothers  had attended a University "Introduction to Computers" course, and within weeks, had taken the advice of a University staff member (whom I would work with 10 years later), to buy the next best thing. It was bright white (dare I say it, just like Apple's yet to be released new "snow white" look, long before the IIc or Mac II's would be released), and had a black and silver aluminium logo. It was a Unitron. A U2000, complete with an elegant grey keyboard with white key symbols. It was packaged in a brown cardboard box, with coarse blue and red stamped Chinese writing, complete with photocopied manuals from a country I didn't even know existed. And it worked just like the Apples at school! But with this one, I was allowed to look under the cover... Wow, a bright blue thing full of lots of black bits and plug in parts that made it work!... this was my first introduction to the world of logic.

With my new found "other cheaper Apple", I approached my father. This time, rather than passing out as he did with my first brave attempts with Apple's pricing, he agreed! And I too became the proud owner of a Unitron, complete with floppy drive. For the next two or three years the Unitron became a fascinating study tool, with it's never ending world of digital design, and the complexity of it all that took forever to discover. And it was in Year 10 at high school (Junior High), that I had the opportunity to experience working in this industry. I finally met the man who was importing the Unitrons. Even better, he agreed to hire me part time. Over the next few years I got to know him well and I repaired Unitrons, studying every board and model they made, including the bizarre array from Chinon to TEAC of Apple compatible drives and a plethora of "brandless" Apple Clones and peripherals you could only identify by their shipping scars. I worked with their corrective correspondence, their dodgy manuals, the photocopied Apple schematics with Chinese mark-ups over the original Apple identification, all whilst adopting the "self help" approach to repairing and replacing logic chips in the clones. Unitron shipped separately "ROM Packs" for U2200's to bypass Customs, as the U2200 was sold and shipped as a CPM machine; and then later upgraded to be Apple II-compatible using these ROM Packs. This was a successful method of avoiding legal issues, which was also adopted by Zeus, amongst other manufacturers.  It was the dodgy underworld copy of another world I didn't even know existed. The world of the real Apple.

In 1983, an Apple IIe appeared in the 'for sale' section of the local paper. It was being sold by a Singaporean student who had finished his University degree and was about to return home. It was the right price. I sold all my Unitron bits and bought my first real Apple. After only a few minutes of studying what was under its lid, I realised what the Apple was all about. Quality. Incredible quality. I had been converted, never to return. Several years later I would apply for a position at the local University to work in their computing centre. I got the job. Over the next five years, I became a qualified Apple service technician, studying and repairing everything Apple whilst endeavouring to unlock the secrets of computer design. In 1991 I met the guy who would show me how it all came together, who introduced the engineers greatest friend; the magical 'Oscilloscope'. Up until now, my 'solder and try' approach wasn't working too well. Dave (who had a company called Zelcon) showed me how to use the oscilloscope to watch the processor initiating those first critical boot cycles after reset. This was the most important part of any processor design and the key to making them go. During 1991 I designed and built my first and second computers, based on the Apple II and the CoCo respectively. This would be the first of many that would lead me to where I am today, designing electronic products.

But who is Unitron?

With the time I spent with Unitron, I soon became very familiar
with their signature blue PCB's, snow white soft plastic cases,
and lots of Chinese characters. It was also very apparent they
were made in Taiwan, as I always went home with at least one
"Made in Taiwan" gold and black sticker on my shirt. These
adhesive labels were on everything. Shipping was always
from Taipei, and the two main models were the U2000 and
the U2200. It wasn't until many decades later, that
information about the 'other' Unitron came to light, thanks
to the internet; the Brazilian Unitron in Sao Paulo. The supposed  original
Unitron. However this Unitron resembled nothing like the Taiwanese Unitron. The Brazilian boards were green with yellow overlay, their manuals were direct copies of Apple's or re-written in Portuguese, with the Brazilian Unitron products featuring different cases and keyboards, ID labels and even their logos were completely different. To date, through general research, and with information from Europe (which also received a significant numbers of Taiwanese Unitron's), it would seem this Taiwanese Unitron was operating independently from the Brazilian outfit. Everything about the two was different. With a write up in "Asian OEM" from 1981, it described the Taiwanese Unitron as the Headquarters to a new Taiwanese technology company entering the computer market; and it would seem Unitron was cloning Unitron.

Some of Unitron's Apple II and IBM PC compatible Motherboards and Peripheral Cards
Unitron 16K Language Card (Prototype)
Unitron Model Number: U-2090

Unitron produced two Apple compatible motherboards before moving into the PC market exclusively. Their initial PC offering was the U-2900T IBM XT compatible which was followed up with the U-3900 IBM AT compatible. Their first Apple compatible was the U-2000, which was cloned by hand direct from the Apple II Plus motherboard. Unitron did include a few subtle changes to their version of the design, which included a different power receptacle to suit their component suppliers, including various Asian sourced devices, such as the cassette jacks, colour trimmer and crystal circuits. Their second Apple compatible board was the very popular U-2200, a dual processor (6502/Z80) which included a fully vented power supply by the Teapo company in Tucheng, a recent spin off of Sampo. Teapo flourished and went on to lead PSU manufacture worldwide; Unitron eventually abandoned Apple compatibles and continued manufacturing PC compatible monitors and peripherals until they departed the Unitron-branded computing market by mid 1986, moving their business to mainly OEM manufacture only.

Unitron Z80 Card
Unitron Model Number: U-2076

Unitron 80 Column Card (Production)
Unitron Model Number: U-2063-2

Unitron Parallel Printer Card (Prototype)
Unitron Model Number: U-2081

Unitron Disk ][ Controller Card (Apple Version)
Unitron Model Number: U-400

Unitron U-2000 Motherboard (Apple II Compatible)
Unitron Model Number: U-2000

Unitron U-2000 Keyboard (DIP16 - Apple II Compatible)
Unitron Model Number: (unknown)

Unitron U-2000/U-2200 Power Supply
Unitron Model Number: THB-43H (U-2021)

Unitron 16K RAM Card
Unitron Model Number: <Unknown>

Unitron U-2200 Keyboard (DB15F - IBM Layout Version)
Unitron Model Number: (U-2235)

Seasonic (TAIWAN)
Unitron PAL Color Card
Unitron Model Number: C-002

Unitron U-2200 Motherboard (Apple II & CP/M Compatible)
Unitron Model Number: U-2200

Unitron 16K Language Card (Production)
Unitron Model Number: U-2090 (H003)

(Note: Artwork suffers from pad/track/via clearance errors)
Read Only Memories (PROMs)
Read Only Memories (UV EPROMs)
M2732 - 4K x8 - DATASHEET
M2716 - 2K x8 - DATASHEET
TBP28L22 - 256W x8 - DATASHEET
Read Only Memories (UV EPROM)
D2732C - 4K x8 - DATASHEET
UNITRON 6 [2732] (ROMF8+F0)
Read Only Memories (UV EPROM)
M2732 - 4K x8 - DATASHEET
UNITRON6 [2716] (ROMF8)
Read Only Memories (UV EPROM)
M2716 - 2K x8 - DATASHEET
Read Only Memories (UV EPROMs)
M5L2732K - 4K x8 - DATASHEET
Read Only Memories (UV EPROMs)
D2716 - 2K x8 - DATASHEET
(Initial motherboard release)
(Initial motherboard release)
(Production release)
(Production release)
Unitron 80 Column Card (Prototype)
Unitron Model Number: U-2063

Read Only Memories (UV EPROMs)
Unitron Parallel Printer Card (Production)
Unitron Model Number: U-2081

(Note: 4x uPD2114 SRAM's for video memory)
(Note: Artwork suffers from pad/track/via clearance errors)
M2732 - 4K x8 - DATASHEET
M2716 - 2K x8 - DATASHEET
Unitron U-2091 Analog Disk Controller
Unitron Model Number: U2091 - Suits TEAC FD-55A Disk Assy

U2091 - Analog Disk Controller Board
U2091 - Based on TEAC FD-55A
Apple Ref: 341-0027-00
Apple Ref: 341-0028-01
DM74LS471 - 256W x8 - DATASHEET
Apple Ref: 341-0020-00
Keyboard Controller (Toshiba)
Read Only Memories (MASK PROM)
M2732 - 4K x8 - DATASHEET