Never heard of MegaDos? That is because it is my own creation. A TRS-80 Type 4 that can run MS-DOS, Windows 3.1, Coherrent, Xenix, Linux, OS/2, play DOS games and run DOS Utilities from the 1980s and 90s!
Left is the original TRS-80 Type 4 I bought. It was dead. Right, Same machine running Windows 8.
Here is the TRS-80 Type 4 after installing an i5 3.1Ghz Motherboard, two 4TB hard drives and Windows 8. It is amazing how upgradable the TRS-80 really is.
This is not an arcade project like most of my diversions, but it still relates to preserving old technology.
I have had this project idea rattling around my head for a long time. I wanted an old computer with modern insides that I could use to play DOS and Win 3.1 games and utilities. As I thought about it I realized I could really make this a big project and also run alternate operating systems using Virtual Machine software, run Windows 3.1, Win95, Win98 and finally have some fun with all the old software I had from the 1980's and 90's.
Originally I wanted to convert an IBM XT and monitor into a modern computer. I actually bought an XT and monitor but as I researched it I discovered that the system I had was a 5150 model which was the very first PC IBM released. It had odd card spacing and was the only one with a cassette jack. It had everything still in it and might even work. I could not cut it up. It was too rare and in too good of condition so I started looking for alternatives.
I first used a TRS-80 Type III in high school. It was my first computer programming class. There were only three computers in the entire school system at that time and all three were in the storage room we used as a computer lab. The teachers did not have computers and the administrators did not have computers because they had no clue what to do with them. I remember it very well. After the first week of class there were two of us in the class who knew more about programming than the teacher. I know that sounds like a high-school thing to say but in this case is was literally true. Our instructor only knew the very basics about BASIC. We learned from the manual and programming assignments were nothing more than a nuisance since we were already working on our own personal projects which were more advanced. You can see the TRS-80 has some nostalgia value for me since it was my first.
This page is my documentation of this conversion including random thoughts and sources as well as interesting websites I found on this journey.
I bought a dead trs-80 model 4 on ebay for 79.00 plus 39.00 shipping. I then sold the insides of the TRS-80 for $46.00 on ebay. All I needed was the case, floppy drives and keyboard.
Someone had taken it apart previously. Unfortunately they did not realize that they had not removed all the screws so tried to pry the case apart. I was able to sand out most of the damage.
It was in pretty rough shape and very dirty. It was obviously stored in a barn for years.
Everything needed a cleaning.
It had 64k of ram(expandable to 128k!).
I thought I would need to paint the case. I was going to paint it Gunmetal Gray to match a Type 3 case. My trs80 had a layer of darkened plastic from UV exposure which also scratched off easily into toxic dust. I used a Magic Eraser with water to rub the plastic down. This took off the darker yellow down to the white plastic in a few rubs and the wetness kept the dust down. It also took off scuffs and black marks easily making it look almost new. It cleaned up so well that I did not have to paint it. That was a little disappointing because I really wanted it to be gray like the computers I used in high school, but I am learning to like the white original plastic.
The Type 4 was introduced in 1985 as the final in the trs-80 line and remained in production until 1990. The firstTRS80's were limited to upper case only which allowed Tandy to cut the cost of manufacturing by $5.
Here is a great video history of the machine https://www.youtube.com/watch?v=ycjNyud0RMc
Find TRS-80's on eBay:
My system now has two 4TB drives disk storage. All trs80's ever produced did not have that much memory capacity all total. It would take over 22,000 360k floppies to store 8TB of information. It would take 125,000 64k memory TRS80's to total 8TB of memory. I know I am mixing memory and drivespace comparisons but it is amazing how little they had and still worked.
This was not just a project to play games but to preserve these older computer programs and historic operating systems in a way that makes them usable. I have included all the manuals and other information I could find. I was able to uncover some private libraries of documents and scans which I added to this collection.
I looked at options including building my own system from a motherboard, CPU, memory or getting a bare bones system or one of those all in one mini-systems. The bare bones systems were too big. The mini systems did not have everything I wanted or were not as powerful as they needed to be. I wanted to use at least an i5 processor since I plan to run virtual machines. I have no experience with VM so I do not know what they need but it sounded good to me. I finally decided to build my own system and buy the components myself so I could make sure everything fit.
I opened up the case to see what I had to work with. At first I thought there was plenty of room to shove a modern computer in there. It seemed so roomy. It turned out that I barely had enough space to fit the computer in.
Here is the opened case.
It was produced 2/18/1984.
I removed all of the unwanted components. I kept the full height floppy drives because I did not want to figure out how to remove the face plate and remount it. I also thought that I might get an adapter that lets me actually use the drives someday.
There was no way I could use the CRT. I needed a higher resolution monitor. I also wanted to use a modern flat panel. I needed a 12 inch monitor to replace the CRT.
Could I use a laptop monitor with adapter?
No, a laptop monitor requires an LCD controller. I found out it is not just a monitor but needs other electronics to work. You can't pull a monitor off a dead laptop and use it as a monitor by wiring up a connector and plugging it in. It is possible to connect a laptop monitor to a computer but requires a lot of circuitry.
I found some 12 inch models available including the Panasonic 12" Toughbook CF-VDL02 LCD Monitor
ELO ET1220L 1220L 407688-000 12'' SERIAL & VGA TOUCHSCREEN LCD MONITOR , Tyco Electronics 1215L 12" LCD Monitor - Gray. I finally picked the Norca PT1212 LCD Monitor
A few companies still make 12 inch monitors for point of sale terminals. These use older technology which means they do not have a great contrast ratio and do not have a good angle of view but they are still very usable and a huge upgrade over the original monitor. I found one on ebay but it took some searching. Some sellers want way too much money for these. Then I found a 12" monitor for $30 shipped. I finally found a second one for $30 and $20 shipping but this spare had no power supply. Once I saw the power supply of the first one I bought, I realized it was very basic and saw the watt rating so dug out an old laptop computer power supply from my junk box with a similar rating. The connector was a regular circular power connector, nothing complicated, so I pulled an old power connector end out of my junkbox and wired it to the laptop power supply. Now I have an extra monitor so may still convert an XT someday.
The bezel was curved for the CRT. I hated to alter anything on the computer the the bezel is one thing that had to be changed. I removed it, cut down the corners so my flat panel would fit within the window area, then used some bondo and plastic strips to fill the gaps. I painted with black primer, then a textured spray, then a double coat of plasti-dip spray. The Plasti-Dip spray gave a plastic look and feel. It is not a glossy or flat spray paint look.
This is the Norca PT1212 LCD Monitor I got from ebay. The company name may change but the model number seems to stay consistent. I believe a number of companies sell the same monitor under their own names. The image looks yellow but that is just the photo flash.
Here are details on the monitor
Model Model PT1212 12 inch 800x600 with svga input.
Sold under the name Norca in black but possibly other names.
This was originally a POS monitor so they show up from time to time as companies upgrade.
These monitors are available on eBay. You may need to setup a watch because they appear about once a month.
I stripped off the plastic.
Cut up the bezel and began adding plastic strips.
I made sure the screen showed through and would not be cut off.
I applied bondo to smooth it out. This took several sessions of apply/sand/apply/sand.
I used these disposable plastic razor blades to smooth the bondo. They are great for small bondo jobs because the bondo peels away from them after it dries so you can re-use them, not that they are expensive anyway.
These blades are available on eBay:
The nearly complete bezel.
The bezel before final sanding. Some primer helped show the spots that needed extra filler to be perfectly smooth.
My final bezel after painting.
Here I attached the bezel to the monitor and mounted in the case to test the fit. It just fit. Another fraction of an inch in any direction and I would have had a major problem.
Here is the front with the monitor installed. It looks factory made.
I found this great site with information on this computer series. I have digital versions of all the documents listed on this site. Since I had a TRS-80 it only seemed right that I have a large digital library of TRS-80 books and manuals on it. Check out Trs-80.com which is a great resource.
I looked at a number of options for the keyboard and decided to keep the original keyboard.
I tried a test fit of a modern keyboard. It actually would have fit. The keyboard can easily be replaced with any 18 inch wide keyboard. A Keytronic black keyboard would work nicely because it is black and has the click-key feel of the original IBM keyboards. I did not want to replace the original. I wanted this computer to look as original as possible from the outside so had to make the original keyboard work. If you had a unit with a missing or damaged keyboard or just a shell, then a new keyboard would be a great option.
If I were to use a key encoder then I needed 64 inputs for the 70 key keyboard(num keys were duplicates) plus a shift key to enable alternate keys. The ipac was only 32 or 56 inputs so I would have needed two no matter what.
This would be expensive for an ipac so I looked at the gp-wiz40. This had the same problem in terms of maximum inputs and I do not think the gp-wiz offers a master-shift option which would be necessary due to my limited number of keys. Also I could not find any information on the gp-wiz40 eco options such as can it be reprogrammed, does it store this information in a chip or does it have to be downloaded on boot up by software, no basic information at all not even in the PDF documentation. In the end it did not matter because neither an ipac or gpwiz would work. It simply would not work with a matrix type keyboard.
This is the keyboard connector that plugged into the motherboard. The keyboard has no circuitry on it. It is only a switch matrix. This makes it easy to rewire to another matrix key encoder.
Here is the pin-out. I took a continuity meter and figured out the address lines based on the reference manual which listed the chip output lines. The manual had no keyboard connector diagram so I had to figure it out.
Pins facing you with cable going down and taper of connector down.
1 2 3 4 5 6 7 8 9 10
R1 NC D1 D3 D5 D7 A6 A4 A2 A0
R2 NC D0 D2 D4 D6 A7 A5 A3 A1
R1 and R2 are the lines to the reset switch.
NC are no connects and you can see in the ribbon cable that these extend about an inch out of the connector and the silver line ends without connecting to anything. You can use this short stub line to identify the pin numbers for 2 and 12 which makes identifying the others easy. Address lines are d0-7
The Dx and Ax are the address and data lines as shown in the hardware manual for the trs-80 Type 4.
My plan is to reassign Break and Clear to act as Del and ESC. Reset will be the reset/power button.
The number key pad actually uses the same addresses as the top number buttons so there is no difference between pressing 1 at the top and pressing 1 on the number pad. The computer sees them as exactly the same key press. This means there are 70 keys but not 70 key codes.
When you have a keyboard that is missing keys you can always use the virtual keyboard which is built into Win7 and later. There are also free virtual keyboards on the web but the Microsoft one that comes with Windows works fine. This kind of program can be handy if you need to press a function key that is not on your keyboard or some other key if you cannot remember where it is mapped.
You can access the screen keyboard in Windows by selecting Start, Programs, Accessories, Keyboard or if you do not see it, type Keyboard in the search box for the start menu and you will see On-Screen Keyboard appear. Pull out a shortcut to you can access it easily next time.
I liked the Windows version best because it included the end/home and other keys.
I first tried to build my own crossover matrix using a hacked usb keyboard. I was pretty sure this would not work so laid out a quick test and found I was right. It did not work. There was no way it would work because the matrix layout was different and if I tried hooking up the keyboard keys I would end up with crossed wires so pressing one key would activate multiple keys on the keyboard circuit. The matrix was not the same which I expected. I had to find a better way.
Here is my failed test board. This is how far I got when I was convinced it would not work and had to abandon it. I can still use this board for another emulation cabinet project as long as I have a limited number of inputs so I will hold onto it.
After a lot of research I found a Pi3 key encoder here http://piengineering.com/custom/xkmatrix.php
This encoder is for industrial controls and can turn any switch into a keyboard press. It will support a lot more than the 32 or 56 key limit of the ipac or gpwiz. This is the board I bought. The software sounded really easy to use to setup a matrix keyboard. It was perfect because it was matrix ready. Regular encoders like the ipac are for switches. If I had used one of these then ghosting would be a major problem but the Pi3 made it easy. This board is actually really nice. For the price, I may consider using it for an emulation cabinet in the future if I have one that needs a lot of keys. This company should promote their Pi3 for arcade use too.
Closeup of the Pi3 key encoder.
Here is another similar device
and another project where someone made a 20 input unit
Various Key Encoders:
There is a super cheap encoder board on ebay called the Zero Delay Arcade USB encoder. Here is a review of that board http://thelair.me/zero-delay-arcade-to-usb-encoder-review/ It would not work for my 70 key keyboard because it is limited to 12 buttons plus arrow keys but might be a good cheap option for another emulator project. I did not need it but bought one just because it was so cheap and wanted it in case I needed it.
Zero Delay Arcade USB Encoder Cheap:
I made F1 a master-shift key or in the terminology of the key encoder, a Layer-2 switch key which switched to Layer-2 on the down stroke and back to Layer-1 on the upstroke. This lets me use keys for other functions. For example, I programmed it so the number keys 1-0 were available as function keys when pressing F1 so I press F1 and 1 becomes the real F1 and 2 F2 etc. I also programmed alternate keys for Home/End/PageUp/PageDwn, Clear is backspace but the F1-Clear is Delete. I had to print out a cheat sheet to remember all of the keys but I can always use the virtual keyboard if I need for windows too. The configuration software makes it easy to reprogram keys(with a keyboard plugged in, but I never tired programming using the virtual keyboard) so if I run across a game that needs a key I have not programmed I can easily add it to my Layer-2.
Here I am testing the keyboard matrix with a continuity meter to figure out the matrix layout.
Here is the original keyboard pulled out.
My manual page for the Type 4 which has a partial matrix but no connector pin-out.
I used Passmark to test the keys.
Here is the Pi3 board I received.
This is the software used to program the Pi3. You connect your matrix and a usb keyboard. Press the button you want to reprogram and a window opens where you select your options and press the key you want assigned. You can also assign different up and down strokes.
The Sun Type 4 keyboard uses the same foam pads as the trs 80 model II, 12, 17 and others. The keys are also interchangeable. I do not know if the keyboard is the same or not.
Watch this video for information on TRS-80 keyboard repairs https://www.youtube.com/watch?v=Dlp1guSPzEc
The Model 4 z80a is running at 4mhz but drops to 2mhz in model III mode. I think a 5 processor 3.1Ghz will do a better job.
These computers originally had one or two Double Density 5.25 floppy drives. You can insert 2 drives in one slot,they are supported but these were distributed with double height drives instead of single height.
This is the back of one of the floppy drives showing the manufacture date of Feb 16, 1984. I also purchased a 1.44meg USB floppy drive. I do not think I even own a 1.44 floppy but thought I should buy them while they are available in case I run across some 1.44 software at the thrift store(which does happen from time to time).
Bottom shot of this Texas Peripherals model 10-5355-001 Floppy Drive
Close up of part number.
Connector 9 is the one that goes to the LED. It only has two wires in the 4 conductor connector. I wanted to wire this LED to my hard drive light so it would flash with the hard drive. I was happy to find the LED went to a connector because it meant I could wire in my hard drive light without modifying the floppy drive at all. I took a pin header and soldered my wires to it, then inserted in the number 9 connector.
Here I am testing the LED connector.
Windows 7 does not support 360k or 1.2meg disks. You may be able to install older drivers from previous versions of Windows. Linux still supports floppies but this functionality must be manually added or manually mounted I think.
Here is a good article on using a 5.25 in a modern computer: http://ascii.textfiles.com/archives/2503
which recommends this card http://shop.deviceside.com/
The card looks like a great option and I may get one if I need to actually use floppy drives.
There is a mod to convert these floppy drives to use a certain type of CD-ROM drive. I did not bother because CD-ROM is as dead of a format as 1.2Meg floppies. Besides, I have a usb CD drive and can connect it if I need to access a CD.
I wired up a usb wireless networking card so I can also access my network wirelessly. I ran a network cable out as a backup too. The only other external connectors I needed were USB. The video is self contained and so is the audio. I do not need a microphone and can use a USB microphone if I want one later. I did not want to cut the case if I could avoid it. Fortunately, there were the old connector slots which were poorly placed under the back. I ran my network cable and some usb extension cables through the connector hole out the back for easy connections when needed or the cables can be tucked under the machine when not needed.
DosBox will be a major part of this system when it is completed. I tried some random dosbox front ends with great disappointment. Some links were dead and the frontends I tried were useless, poorly programmed, poorly documented. There was no indicator on the website I found about which was the best or which were better than others so I was left to randomly pick them. Some of the webpages for these frontends were so sparse I did not bother downloading. If they care so little for their software that they do not put up a proper webpage with basic information or even a screen shot then that tells me not to waste my time. After a few failures there was no reason to keep testing bad software. Considering how great dosbox is, it is disappointing to see such "front ends" are all that we have to go with it.
If you are trying old files then I suggest you virus check anything you plan to run after unzipping. Many original games were infected and redistributed in the 80s and 90s by BBS just as they are distributed today on bittorrent. These files came from many unknown sources so may be infected, though I would hope whoever put the collections together had an antivirus program running that would catch any viruses, but who knows.
I had a chance to dig out my old versions of Doom Duckhunt and Wolfenstein with the Simpsons mod and many other games I had not played in a long time.
I collected cheats for games in the way back when of the Internet, back when it was not public. The cheats folder has cheats and solutions for many games as well as solutions for Leisure Suit Larry - all versions and other games. These are really handy now when there is no floppy drive anymore for copy protection to work.
I also had a huge collection of games and utilities which are not available anymore. I went through my dos games and utilities over the course of a week to pull out ones that I thought still were usable.
I also setup a complete MESS system. This is the first time I setup a complete mess system with all available roms and games for every supported system. It was difficult. There are a lot of "help" files out there but few are actually helpful and none answer basic questions like where do CHD files go, in the roms or software folders? Some sets I obtained had the software under a roms folder but that made no sense to me and some had the files dumped in a roms folder not under a system name which also seemed wrong. How do you setup snaps in MESS? The old snaps had files that match the system name but now there are folders with subnamed games which makes more sense but it did not show up when I used those as snaps in the MESS front end. I figured out the answers to these and many other questions on my own but it took a long time.
The MESS UI apparently has a bug in it. When you set a software folder in the main configuration, that entry is completely ignored. To get software to appear in the software window you have to go to each system and right click, select the software tab, then point it to the software folder and suddenly the software titles will appear. This makes it very hard to use because you have to effectively setup every system individually plus some show wrong results. For example, some will not show games but individual roms so instead of gamename.7z it shows 0001.bin 00002.bin which are obviously unplayable because those are part of gamename.7z The game names are also displayed poorly(or named poorly) because the software is in lower case which does not look right. It would seem that there would be an option to display software titles with title capitalization so they look right.
I tried the MESS front end QMC2 after reading a number of recommendations. It unfortunately did not work. I tried to get help but to ask questions on the forum you have to register at
I did that and followed the instructions but no one ever approved my account(Update, it was approved, about 3 months later after I had long lost interest in QMC2). I have to wonder why someone bothers to put up a forum if they are not going to let those who have questions participate.
I put together a huge collection of shareware CD's. Back in the 80's and 90's there was SIMTEL which had a giant repository of utilities and games, freeware and shareware for DOS and Win31. I found these and added them to my system. I have several SIMTEL, various other collections, the Ham Radio CD-ROM.
Did you realize Windows 3.1 and following versions were only released in 1992 and sold until 1994 when Win95 was released? It was only out two years! I found my old Windows 3.0 installation and also a Windows 1.0 and a set of DOS disks with various versions.
I plan to use these to make virtual machines with VMWare. If you are not familiar with Virtual Machines, they let you run an old operating system on your computer as if it was a windowed program. Check it out here:
I also found a UNIX like OS called Coherent. I remember backing up my 286 to floppies, wiping the hard drive to install Coherent, getting it to work, realizing I had no software to run on it and could do nothing with it, reformatting with MS DOS and recopying everything back to my computer. For some strange reason I want to make a virtual machine of Coherent and do it again. Repeat the same story and replace Coherent with Xenix. That is my next plan.
Here is a video of someone installing Xenix on another Virtual Machine system:
I love that someone so young has an interest in Xenix and made the above video.
Some 911 Emergency systems ran on Xenix as late as around the year 2000.
Here is an overview of Xenix
ScummVM emulates many old games(not exactly emulates but let's say that is the right word for now), however it is not 100% accurate for many of them. You may find some areas of a game do not work or you may not be able to finish a game with ScummVM. This is why I also kept the original games(plus cheat guides) which can be played in dosbox or under Win311 or on a virtual machine. I have a full ScummVM set but also various releases of the original games. These still show up in thrift stores too.
I am now glad I kept all my old utilities. What if you find an old file that you need to open in Microsoft Publisher 1.0? What do you do? I now have a system that lets me open even those old files where I saved information in the 90s.
Teledisk images end in .td0 and these are disk images. You will need to uncompress them to a virtual floppy to use them or uncompress to a virtual floppy and then make an img file for dosbox. I have a lot of Teledisk images to convert.
You might be able to use software like this http://vfd.sourceforge.net/
to expand to and save a new image file. I have not tried it.
You can find information on teledisk extraction of .td0 files here
This page has a utility to convert teledisk to imagedisk format which can be used by VmWare machines.
The same guy has a page for converting other image formats like CPT:
It is supposed to be possible to install win95 and win98 on dosbox according to:
I think I will use a virtual machine instead.
I also have a huge collection of viruses from the 80's and 90's. I plan to create a virtual machine where I can safely play with them.
This is more of a preservation project than a gaming project which is why I am including a lot of things that are not games.
You can find the vmware virtual machine guide here
You will want to download the vmware player which is free. This is what runs the disk images. To import files into your created virtual machine see these instructions
Unfortunately ehow is a very poorly designed and annoying site with all the spam popups but get the info and leave as soon as you can.
I can create a virtual machine with XP and other OS's because I have lots of valid serial numbers for installations from dead systems and laptops I have owned in the past which I can use in virtual machines.
How to run a maxosx vm and import from windows:
how to load an ISO image as a virtual drive in vmware
how to add files to a msdos on a virtual machine
Note that a .cdr image is a .iso image so rename it to mount. 99% of the time you can also rename a .bin from a bin/cue set as a .iso and it will work unless the cuesheet is complicated(more than one entry).
How to install dos and win3.1 on vm
Note that it is easier to add files to a dosbox than to a virtual machine so dosbox is easier for many uses. The ways to add files to a dosbox session is to drag and drop on the files into the folder used as a drive. To add to msdos running on a virtual machine is not so easy. You have to create an iso with the files and attach as a cd or create a floppy image and attach as a floppy. You can also share a networked folder but that is only for windows unless you setup some kind of networking for msdos which is unlikely to communicate with windows.
I have now found a use for my PC Fix It CD. The PC Fix It Cd is a home-made utility set for working on dos and windows 3.1 systems, and some for win95. It is something I put together in the 1990s to work on computers and had lots of utilities any computer technician needed. It started off as a floppy disk but as time passed it grew into multiple floppies and when CD's became the standard I switched to a CD-ROM, which was made of gold foil and cost $35 each at the time. When you got a buffer underun error trying to burn one of those you cried a little before throwing it in the trash and trying to burn the next disk while hoping the computer did not stutter.
There are way too many games to install them all. I also have multiple versions of many games because they were released by different groups or may be different versions. This set is not like mame front ends where you select a game and play it. You need to pick the game you want and install it, maybe unprotect it too. That is part of the fun of working in DOS.
Now I am looking for one of the ancient 5Meg, 8 inch platter, hard drives that went with the TRS-80 which is dead to convert to a modern drive. I may get a vintage tape drive, if it has visible tape wheels, connect the power advance to the hard drive light so when the hard drive light is accessed the tape moves and put a usb sata drive inside it.
I found a Univac simulator but have so far been unable to get it to work.
I found a Cray-1 simulator. The irony is it is written for dos so you have to use dosbox or a virtual machine to simulate a Cray 1.
This project became overwhelming quickly. There are so many older systems that it would have taken months if not years to go through each one, obtain the files and software available and make them work. I had to focus on a few major systems and fill in or merely archive the others.
I focused on Apple, C64, Trs80, Univac, eniac, and especially Dos/Win311 as well as my virtual machines. I setup MESS with all available software and ROM sets, however there was no way I could go through to test/setup each one.
I decided not to use HyperSpin as a front end or to use any real frontend for that matter. There are so many games, it is so huge, and many require installation or unpacking or unarj'ing or unzipping so the command line is the way to go. I could have spent years trying to configure HyperSpin to work and then only touch on a handful of games so it was not worth it especially when you will almost always drop to the command line anyway or have to run a virtual machine then run the game.
Here is the partly assembled system. Motherboard and power supply with keyboard. I had to replace the power cord but kept the original power switch.
I purchased a power cable strain relief to install my new power cable. It was hard to find until I figured out the right keywords to search for.
Here is the final system being tested.
Close up of the hard drives and power distribution block that feeds the monitor, main power supply and sound card board. I took a set of speakers, removed the driver board and used it with a set of smaller speakers. You can see how space became an issue. There is no way I could have used a regular CRT unless I removed the floppy drives.
Completed system running Windows 8.
Resources I Found
Here is a site for dos menu programs
You can download DOS games here
This site lists old computer fonts
Here is some good resto and history
I found some files for the trs80 on how to build a cassette cable but they were damaged. I was able to use http://www.pdf-online.com/osa/repair.aspx to repair them for free. Great site to repair PDF files.
Here is an ASCII art text generator
Another source for ASCII art
How to add mouse support to msdos
The TRS-80 Color Computer actually had a mouse! This was the perfect accompanyment to my conversion. It did not originally go with the Model 4 but I don't care. It looks like it could have and it is an old mouse.
This is the original TRS-80 Color mouse
Here is the bottom of it.
These are the insides. That is a steel ball in the center. The mouse is very heavy but well engineered.
I tore open three different mice before I found one that worked. A regular mouse had too big of a board, the finger mouse above was too long, finally I found a very flat mouse called a Slim Mouse which fit.
This is the board from the Slim Mouse.
There was not enough space to use a micro switch so I cut a leaf switch off an arcade button controller.
Here I have installed the leaf switch for left-click. I considered a number of options such as making the big button so the right side was click right and the left side click left or possibly cut the button in half, but that would require some major re-engineering and there is not much space in this little mouse. I decided to keep the original button and not alter how it operated.
Here is the final mouse. You can see the sensor on the bottom. It offset due to the way I had to fit the board but it works just fine. These lenses have a very narrow depth of field, about 1-2mm. If you are 1mm too far from the surface the movement is not smooth. If you are 1mm too close, the movement is not smooth. I had to do some smoothing on the collar that supported the ball to make the bottom of the mouse interior flat and the plastic then was the perfect distance from the surface to give a good movement.
Here is the final mouse. I added a button for right click. I hated to drill a hole but right click is necessary and there was no better option. I put it where it was not obvious and used a button that was both small and looked like it might have been used in the 1980's.
I also used the original cable by soldering a USB connector to the end after cutting off the large cassette data type connector and wired the other side to my mouse circuit board. This allowed me to keep the original strain relief and original cable so from the outside it looks exactly like the original except for the button on the front and the sensor instead of a metal ball. It is much lighter now too.
TRS-80 Color Computer Mouse compared to modern mouse.