Is This Australia's First PC? March-1978
Or just the most modified TRS-80?

TRS-80 Model One.
26-1001 Model 1 Level 1 4k CPU/Keyboard.

Industry Links
George Julius, Australia's Father Of Scientific & Industrial Research.
Brian Conlon's web site devoted to Automatic Totalisators Ltd.
Powerhouse Museum Automatic totalisator.
An Unlikely History of Australian Computing: the Reign of the Totalisator
CSIRAC Australia's first electronic digital computer
The World's First Large-Scale, Multi-User, Real Time System.
Was George Julius the inspiration for CSIRAC, Australia's first electronic digital computer?
My Early Tote Years - Don McKenzie
Is This Australia's First PC?

History and Serial Number

March-2008 Thirty Years Later:
I decided to write this before I forget it all, or simply become no longer capable of doing so. Don McKenzie, Dontronics.

By late 1977, two U.S. Magazines, Byte, and Kilobaud, were reporting on three new personal computers, aimed squarely at the home market. These were the Commodore Pet, Steve Wozniak & Steve Jobs Apple II, and Tandy's TRS-80 Model One. The earlier Apple I was supplied as a main PCB, and you were required to build it up yourself.

It appears production quantities of the Pet and Apple were several months in advance of the Tandy PC, however I was unable to mail order any of the three in 1977. I clearly remember Commodore quoting  that they were unable to send me one, as they weren't geared up for 50Hz and 240V, even though I said it was my problem, not theirs. Apple mail order resellers said they couldn't keep up with local orders, and weren't interested in selling outside the U.S., but Tandy told me that they would be selling the TRS-80 in Australia very soon, and to put an order in, and I should be one of the first on the list to receive one.

So arguably, I have the first PC in Australia, if not, certainly one of the very first. Mine arrived in Australia in March 1978. I would be very interested if anyone has a serial number that is before "028066".
Catalog Number 26-1001D This indicates that it was originally a 4K Rom, and 4K Ram machine. I have no idea what the "D" represents.

Defining Personal Computer:
From Wikipedia, the free encyclopedia:
A personal computer (PC) is a computer whose original sales price, size, and capabilities make it useful for individuals, intended to be operated directly by an end user, with no intervening computer operator.

From Wikipedia, the free encyclopedia:
A personal computer is one intended for individual use, as opposed to a mainframe computer where the end user's requests are filtered through operating staff, or a time sharing system in which one large processor is shared by many individuals. After the development of the microprocessor, individual personal computers were low enough in cost that they eventually became affordable consumer goods. Early personal computers generally called microcomputers were sold often in electronic kit form and in limited numbers, and were of interest mostly to hobbyists and technicians.

Tandy refer to the TRS-80 in this document: "Radio Shack's Description of the Model I" on three occassions, as the model I being a Personal Computer, and once as being a Personal Microcomputer.

Here is another entirely different view: I guess the more I look for answers, the more questions I will find.

What I had was a computer that I could use at home, one I could afford to purchase as a wage earner for myself. I didn't have to assemble it, just plug it in and read the manual. That is a home personal computer, as used by an end user, and the same definition basically applies today. At one point, if you didn't have an IBM, or clone, you didn't have a PC. It will only run on a PC is a very common term. I hear it basically every day, but would you say that Apple's latest MacBook Air wasn't a Personal Computer?

Don's Early Workbench:
Shows unit with original keyboard, two large heat sinks out the back, Electronics Australia programmer, original tape recorder for data storage, new 5 1/4" disk drive, home built LNW expansion interface, and a converted TV for video output.

Pictured above: Note the wall to the left of the TRS-80. Two walls of this room were wall papered with "TOTE" tickets. This was our Bar room. I started off in the family room, then the laundry, the bar, our third bed room, (kids had grown up), and now back to the family room.

I was with ATL, then the TAB, then TABCORP for 25 years. (continuous superannuation, different logos :-)
and a link to the wall paper: About 3/4's of the way down that page you will see a J8 ticket issuing machine. Well, I worked on the previous model, the J6, and the associated control gear. The Tote is an Australian invention, and again arguably the world's first electro-mechanical computer. (Circa 1913) Don't think it's a PC however :-)

Morse Code Generator for the Australian Department Of Communications:
This computer generated all the 5, 10, and 20 WPM morse code that was used for Novice, Ham, and Marine morse code receiving tests by the Australian Department Of Communications from around 1980 to 1986. This was previously done by a punch tape machine, and when I was asked if I could program a computer to do this, I said of course you can. That is the sort of thing that computers are designed to do. I soon found out that you can't get accurate timing for long periods using the basic language built into this machine, so I had to learn Z80 machine code damn fast.

I eventually had to tell DOC that I wanted to drop this contract, as the repetitive nature of the input strings really drove me mad. It was around the time they shifted headquarters from Melbourne to Canberra, so I suggested they get some one to re-write the software on an 80286 AT-PC, as the TRS-80 was getting very dated, and I was involved in too many other projects of my own at the time.

The Main Printed Circuit Board

The old joke about the two new heads, and three new handles? Almost. There are rows of chips piggybacked to others, and a birds nest of wiring running on both sides of the boards, with ZIF sockets for EP(ROM) firmware and character generators.

Custom Modifications.

This computer was the guinea pig for all future modifications that I wanted and needed. Most of the final designs were marketed via User Groups, and local electronics magazines. This meant that every track cut, rewire, and additional IC's were all added to this computer, and in many cases removed, after prototype boards were tested.

Location, Top Left:
Small PCB attached to the main board.  A sophisticated board I designed to control the clock input frequency to the Z80 CPU. Allowed reliable speed shifting during all I/O.

Location, Plug in Board with 24 pin ribbon cable next to Speedon:
Small PCB plugs into the original character generator and extends the socket position to the 24 pin ZIF socket on the face of the keyboard. Used a 2716 EPROM. This allowed for lower case characters to be displayed. More on Gendon later.

Location, Center of board. Plug in 24 pin header cable:
Extends the system ROM via the header cable to the DONMON PCB, hanging out the back of the computer. This was normally fitted inside the case, but as this unit was the prototype for all modifications, it had to be removed on a regular basis, and ended up living outside the case. More on Donmon later.

From Level I to Level II:
Location, Center of board. Plug in 24 pin header cable, and the ROM to the right of this:
Level I was 4K ROM. Level II was 16K in three ROMs. I had to purchase the original upgrade, which was a simple adapter with header cable, and small PCB, to add the extra ROMs. Eventually this was discarded when Donmon came along, and the extra ROMs were placed on the Donmon board, along with the Donmon circuitry.

64K Dram:
Location, 8 chips running horizontally under Donmon cable.
These started off with the original 4K of 4114's, and were replaced with 16K of 4116's when these were first released. Later, additional 4116's were piggybacked three high, to give 48K of Dram. When the 64K 4164's came onto the market, I replaced the three high piggyback with 8 by 4164 chips.  However the Level II firmware would only allow for a maximum Dram size of 48K.

Original keyboard wore out, so I fitted a new one from a Super-80 computer. (Dick Smith kit).
Reset button for Donmon is located top right of the keyboard.

Can't remember why I ended up with two ugly holes in the bottom of the case. No doubt to bring cables, and components out during various stages of R&D :-)

Donmon went through a number of board and firmware revisions.

Close up of the main board I.D.


Gendon ZIF Socket:


Gendon Screenshot:

TRS-80's and System-80's had all upper case characters only. It appears this was done to save a single 2102 memory chip on the main board. After adding that chip, a suitable lower case character generator, supporting circuitry, plus a suitable video driver, lower case could be displayed.

I had "Don's Authorized Modifiers" Australia wide. We were the first to offer 3 line descenders.  All of the others had the letters "y,j,g,p, and q" actually sitting above the base line. These were simply the contents of the original character generators being displayed.

The original character generators in these computers was mapped out 5 bits wide by 7 bits high. (8 bits high with a one line descender) By addressing the generator with an extra address and data line, I was able to map out 6 bits wide by 12 bits high, which is the full available space of one character. This allowed me to output 3 line descender characters.

Many U.S. companies produced kits with descenders after mine appeared, and later System-80's had 3 line descenders.

My Authorized Modifier list looked something like this:
Ray Barrington       Bega NSW
Michael Cooper       Surry Hills NSW
Mick Gulovsen        Glenroy Vic
Rob McAllister       Lower Templestowe VIC
Stuart McMinn        Pascoe Vale VIC
C Nielsen            Apsley QLD
Keith Pakenham       Keysborough VIC
Peter Rich           Ryde NSW
John Ross            Greenacres SA
Ewart Stonach        Ashfield NSW
John Western         Padbury WA

Printdon 779 (Gendon spin off):
A lower case character generator for TANDY LINE PRINTER ONE, and CENTRONICS 779 Printers.
Having used my old upper case only line printer for some time, I became envious of the new Japanese plastic printers and their capabilities. I noticed an AD in a US magazine for a small kit that added lower case for this type of printer for $95. At this point of time, I was a little cheesed off with US mail order companies, so I decided to have a go at rolling my own. Wish I had never undertaken this task, even for myself, as it developed into a real game of adventure. I'm sure Centronics mapped their original rom just to put me off the trail to lower case success. After investing many, many hours into this project, I was able to come up with the full 128 ascii character set, and all those up and down arrows etc., that I had been missing.

NOTE **** Wasn't able to have descenders, as there was only 7 print pins (height) on these printers.

My first printer was a WW II Baudot Model 15 Teletype that I interfaced to my TRS-80. This was later followed by a much lighter Siemens Halske Teleprinter Model 100.

Donmon Screenshot:

Donmon was memory mapped  from 3000H to 37DFH and slipped in between the keyboard and video memory maps.

Screen shot has the address and phone number masked. Why? These haven't changed in 35 years and:
People actually do call in at 23:00 and think it is quite OK to do so.
People actually do phone at 03:00 from the US and think it is quite OK to do so.

The top left corner text alternates between "POWER UP" and "RESET TO" as a system alive indicator.
This monitor program was entered by powering up the system, or pressing reset on the keyboard.

The idea was to have Donmon completely invisible to all operating systems, have the ability to jump to the Donmon monitor program, and return at any time to the program that was interrupted, when the rest button was originally pressed.

Once in the Donmon monitor program, the following drivers were available:
Screen print facility, keyboard driver with shift lock, flashing cursor with control, keyboard beeper, control characters, auto repeat on all keys, lower case video driver.
And the following features were available:
Display character set, Rom and Ram check, ascii and hex display of memory, edit memory, deposit data byte in full block of memory, goto hex address, move blocks of memory, reset memory size without destroying basic text, overwrite a Basic new command, write a system tape, etc. A string floppy version was later written for F800H.

The Donmon short form kit consisted of 2 EPROMS, a bare printed circuit board, and manual at $40AUD and had a 90 day refund offer if not satisfied.

My other Z80 spin offs:
This was a development board based on PBUFF, that allowed a fast download of assembled Z80 machine code to the target board. Required no EPROM burning, and started instantly. Similar development systems of the day, started at several hundred dollars.
Electronics Australia Magazine Apr-94

I recompiled 8080 Tiny Basic into Z80 code, then added the I/O routines to make it tick on my ZLOAD development board. Meant you could write a Basic language program, test it, then burn it into an EPROM when completed.

TRI-colour LED moving message board.
Silicon Chip Magazine Mar-89 Part 1
Silicon Chip Magazine Apr-89 Part 2
Silicon Chip Magazine May-89 Part 3
Silicon Chip Magazine Jun-89 Part 4


A few years into the TRS-80, I designed a printer buffer based on the Z80. Printers of the day had no memory, so when you went to print a large document, your PC was completely tied up during the print. PBUFF was a printer buffer that could be configured from 8K to 4Mb of DRAM. Hardware memory interfacing was done with only a single 74LS00 and a 74LS04. The magic was achieved with software and no hardware multiplexing was used. To my knowledge, I am the only person that was able to achieve this result.

PBUFF sold over 4000 units world wide, well before the internet was known.

Electronics Australia Magazine Apr-94
Silicon Chip Magazine Oct-89
Australian Electronics Jan-88 (PBUFF memory secrets revealed.)
Australian Electronics Mar-87

PBUFF unit shown has a serial interface board fitted on top of the PBUFF board. This allowed for serial or parallel in, and serial or parallel out.
There were many optional boards added to PBUFF.

An interesting footnote to PBUFF:
To help protect the EPROM software, I swapped data bits 6 and 7 to the EPROM socket, and shuffled the firmware to suit. I inserted some interesting text to throw off would be pirates, however with the success of ZLOAD, I had to let the cat out of the bag, as many users wanted my boards for just for Z80 development. This meant that 2 tracks had to be cut, and 2 jumpers connected to make it look like a normal data bus layout. I eventually made this easy by placing pads for this job on the board.

Why Dontronics?
As my product range grew, I seemed to have a (bad?) habit of including "Don" into the product name somewhere. We even came up with a few un-printable "-don" names, that we joked about.

I first registered a business in 1964, and by 1995, felt I needed to come up with a new business name to match the type of market I was now involved in. We had to nominate five names in order of preference on the business name application form, and I came up with various combinations of "Micro", and "Electronics". My wife Cheryl threw Dontronics into the ring, as we were short on the five names needed. Of course, it came back with Dontronics winning the bid, a name I hated at the time.

Now, it has become a way of life. I was able to tell my boss where to firmly place his job, when I was 56 years old. A bold move at that age I guess. I have been fully self employed since 1999, and currently employ one daughter full time, and one part time. It's a nice feeling to be able to do that. I'll be 65 next month (April-2008), and hope to keep Dontronics going for a few more years into the future.

My Mate Mick:
A very special mention of my very good friend and right hand man, Mick Gulovsen. I met Mick at a TRS-80 User Group meeting in the very early days. He was hanging on the correct end of a logic probe, and I was silly enough to think he knew what he was doing, and introduced myself. He has been drinking my beer ever since, and I'm still trying to teach him how to use that logic probe. :-)

TRS-80 On Line References:

Ira Goldklang's TRS-80 Revived Site Model I Page

TRS-80 From Wikipedia, the free encyclopedia

Radio Shack TRS-80 Catalog Catalog RSC-3

Tandy Catalog Numbers for Computers, Peripherals, and Software

Australian TRS-80 Newsletter Number 1. May-1978


Don McKenzie wrote:


G'day Art,

Thanks for your very interesting email. I see you also have a lot to reminisce about regarding the TRS-80, and can understand how the combination of the USAF and Defence Australian, beat me to the punch, when it comes to having the first (PC?) TRS-80 in Australia. I must ask you, did it survive? Do you still have it? I know others would be interested in reading this account of your involvement in this evolving period in Australian computer history, and would like to add your email to my TRS-80 page.

I would like to use your name only, not any email or other personal details, as there may be pending customs, and other 30 year old legal issues. :-)
(IE: Hands up those who didn't have a set of level II's in EPROM?)

Cheers Don...

PS, Art gave me permission to post his email on this page. It appears that the TRS-80's mentioned in his text have gone to heaven.

Art Clarke wrote:


g'day Don

Read your page on the TRS80 with some amusement.

Rest assured that your machine wasn't the first around in Oz but would have no difficulty winning the 'most hacked'.

When Tandy announced the M1 in USA I was working in Woomera SA and had a few  USAF personnel as both close neighbours and mates. One of those mates (VS) and I got together and purchased two TRS80 Model 1 machines in USA and shipped them to Australia, arriving in November 1977.

Not hard to do when you understand that USAF personnel going back to the States were willing to take our cash with them (in their account of course), purchase the desired item locally in USA and then have it shipped to their good pals via MAC flight. Naturally these arrived as 'gifts' to fellow USAF personnel so the one lonely Australian Customs officer wasn't able to do anything about it. After all, the things were going back to the States when those personnel left, weren't they?? Funny how they were 'dead' and given away as scrap about then!

Didn't take long to rework those to 16k Level II, one of which even had genuine Tandy ROMs in it. The other had EPROMs and neither of them had Tandy supplied 16k conversions.

VS later brought in a Tandy expansion interface which proved to be a real PITA, whereas I brought in the first version of the LNW interface as a bare board. That proved to be a much better solution once built, although it too had to be hacked a little to debug it. Feedback of what we found resulted in the improved v2 LNW board which went into all the kits and which won us a couple of new boards for our trouble.

By this time we had realised there was no substitute for the best quality components we could lay our hands on, so being good little fellows we used both his employer (USAF) and mine (Defence Aust) to source what we needed through the wonderful stores systems they both provided.

Both of us were already pretty electronics hardware savvy so didn't take us long to figure a good logic analyser would be rather nice. A bit of fancy footwork and USAF suddenly found itself the proud owner of a lovely HP manufactured unit.  Just happened that VS was responsible for oversight of that sort of equipment too. Of course, one needs a decent 'scope too, so Defence Australia found a need for a nice shiny new dual trace unit (also HP). Never seemed difficult for us to have either or both around when we needed them, either.

Not too much later the LNW-80 main boards were being developed - around mid '79 from memory. One of those duly arrived and was soon assembled and put into service, again being hacked and debugged.

All through this, VS and I were continually adapting and adding to the machines, sometimes even with hardware sourced from yourself.

One of the more adventurous efforts was building & installing a sub board for a new gee-whiz RTC, mapped into memory just above the video hardware, and then hacking the NewDOS-80 OS we were using so that it read the time from the RTC. Quite a bit of patching plus a rethink to put the I/O routines in a small ROM also memory mapped and it worked virtually transparently. Even got the OS to set the time happily although we never did get around to patching the ROM code to use the RTC.

Enhanced graphics was another mod, port switched to overlay the ROMs, a nightmare when it came to hacking the OS to make it all transparent. We did get it done but were never all that happy with the implementation.

A pair of AMD math & arithmetic co-processors (921x's) also went into my machine, VS didn't see a need for it (but he wasn't driving a bloody great antenna array like I was for my amateur station). After several EPROMs got burned with hacked code, even Level II BASIC was using them for single and double precision arithmetic. Even SIN, COS, TAN and EXP were decently quick after that.

Not surprisingly, one common mod to each of our machines (there was a third by early '78) was to scrap the horrible cheap keyboard and contacts, replacing it with a Keytronics manufactured unit of much better quality. Access to gold plating facilities in Defence to eliminate issues with the contacts in those just finished it off nicely.

Somewhere along the line someone (either VS or BK) decided it would be a good thing to have sound. Not the beep stuff then being played with, they wanted full-on software driven audio output. It did get done but I sat back and watched that little circus.

All the machines had double density conversions along with at least two disk drives, purchased as soon as we realised how much of a PITA that bloody cassette tape was and immediately we knew the Expansion interface would allow us to get rid of it. Of course the DD conversions happened a little later, the first of which was a kludged add-on based on the new gee-whiz WD 179x series chips. That gave us LOTS of headaches getting the OS to work with it initially, then NewDOS-80 patches became available and sorted that out.

Funny the people we got to know, probably because we were either military or civilian contractors there was no problem contacting people like Randy Cook, Bill Gates etc. Of course, they were also just starting out and it was all something of a wonder to most of them ("jeez, I'm actually making a living out of this stuff!" was a familiar comment).

I think there is still one of your PBUFFs around somewhere! Probably residing on a shelf in the storeroom near the LNW-80 that's built into a Beehive B100 case. That unit came about in an attempt to reduce RF hash from the LNW-80 in the shack and reasonably successful too I might add. A spray coating of nickel rich paint on the inside of the case plus some extensive RF suppression on cables and ports brought it down to an acceptable level.

Anyway, enough reminiscing, time to get to a bit more software development for the AVR ATMega128 board I'm fiddling with. Don't those things make the old TRS80 look pretty sick!!

regards Art C 

13-May-2010 Trevor Moore.


Hi Don, I read with great interest your article on the old trash80! brought back many happy memories However yours was not the first, I bought mine mid 70's 26101 d Ser 025581. Still have it in a box up the shed. regards Trevor Moore.

(Trevor provided pictures of the unit, including the serial number he mentioned)

Yes I have lived at Mt.Martha for quite some time but not in the 70's
I was not aware of the user group at that time.
I bought the unit from a Tandy store in Sydney rd Brunswick, the salesman didn't know what I was talking about and I had to show him a catalogue from the US. and they ordered it in for me.
I fiddled with many modifications to my unit including lower case mods, and a high speed tape interface, however I always wanted to add a printer but as it did not have the expansion interface I had no serial port.
I was an avid reader of Micro 80 I think it was called, a US magazine for enthusiasts and I came across an interface project for 
Connecting a teleprinter via a current loop, I bought an old TAB terminal which was the size of a small desk which contained a very ancient
Teleprinter,you may be familiar with these terminals, what a mechanical monster ! however with a bit of translation code I was able to print for the first time, of course this old machine was
Based on a 5 bit code and was unable to print the full ASCII set.
My wife banned the noisy monster from the house and I relocated it to the garage.
I have fond memories of the old computers including the Apple IIe which led my son and I to set up a bulletin board called Telegraph road which was part of Fido, who said email was something new ! 
This BB ran on the IIe with a Sider10meg hard drive that cost around $1500 a lot of money in the 80's and a lot of explaining to the wife.

Unfortunately I no longer have the same  enthusiasm for computers, they have become just another tool, but then again I could not imagine life without them !

PS, Trevor gave me permission to post his email on this page. 
Trevor has beaten me to the punch with the ealiest serial number in Australia, but I like to think I ordered and received mine first, as it was on order for several months before the first shipment arrived in Australia. 
Well, at least, we appear to be the first. Just sorry I lost the origional receipt from March 1978. :-)

13-May-2010 Don McKenzie


I ordered mine months in advance, and waited for them to arrive.
I started with a WWII Baudot Teletype, and graduated to a Siemens which I got when I was working for the TAB (ATL). Yes I had to make up an interface for it.
I was having a good laugh about the Baudot yesterday. My now 43 year old daughter said that when it did a carriage return, the house would shake. Sounded more like a cement mixer than a printer.
Also today, I use computers as a tool, and have no interest in getting into the hardware.

Cheers Don... 


Ian Mavric, Tullamarine. Australia

Hi Don, I read your Australia's first PC page with interest and think I have
a Model 1 which I might have purchased before you and Trevors.

See pictures attached, I bought 26-1006D serial number 009911 in 1978.  To
give validity to this (I've lost my original receipt) my monitor has Mfd Dec
1977 on the back of it (picture to follow on the weekend).


1978: Purchased the Model 1, then the EI and disk drives in 1979, a double
density kit in 1982, and a 5Mb hard drive in 1983.


Yes over the years I did quite a few.  The main one is 512K Ram upgrade from
Anitek (you can see the stacked 256K Rams and satellite bank-switching
board) which enabled me to run LeScript with a huge buffer big enough to
hold me thesis in one document.  I replaced the keyboard cable with one
which unplugs, and did the lower-case mod from Dennis Bathory-Kitsz Custom
TRS-80 book and what-do-you-know the computer has a flying lowercase 'a' and
no lowercase descenders.  I also moved the reset button to the back of the
machine where its easier to press and installed a Smart-watch real time
clock because I was sick of typing the date and time every time I booted up.
To make the system robust I installed Eap Co Gold plug 80s and the computer
was just about bullet-proof.  I still use it to make disks for my TRS-80
support hobby / cottage business.

Ian's Web Site is at:

I just checked Ian's serial number at:
and found that it is a later version
and model that has the short keypad, Level II Rom
and 16K Ram

Sorry Ian, it is somewhat later than mine. Cheers Don...