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anchor: modelhunderd
Tandy Model 100
How can you not love this formfactor? Believe it or not, I added the wonderful Tandy TRS-80 Model 100 to my collection a couple of years ago for free. I received it from the original owner, who understandably felt a bit hesitant to let go of it after all those years. Along with the computer he also passed on a tape recorder, a floppy drive with several disks, and a printer—the latter currently in need of new belts.
Released in 1983, the TRS-80 Model 100 was one of the earliest truly practical portable computers. Designed by Kyocera and sold by Tandy/Radio Shack, it combined a full keyboard, LCD display, built-in modem, and long battery life in a compact case. At the moment my unit still has some display issues and the case could use a bit of retrobrighting, so this machine will likely appear in a future Computer TLC episode. Despite its modest hardware, the Model 100 became incredibly popular with journalists and traveling professionals because it could instantly power on and immediately start writing or transmitting text—something that made it one of the first genuinely useful laptop computers. |
Portable computing milestone
1900
System Overview
|
Why Model 100 matters
The TRS-80 Model 100 is widely regarded as one of the first truly practical laptop computers. Its combination of long battery life, instant-on operation, and built-in communications made it a powerful tool for mobile work in the early 1980s.
One group that embraced the Model 100 in particular was journalists. Reporters could write articles on the machine and transmit them over the built-in 300-baud modem, often sending stories directly from hotel rooms or press locations to their newsroom.
Another reason the Model 100 stood out was its ROM-based software environment. Programs such as the TEXT editor, BASIC interpreter, and telecommunications software were built directly into the machine. This meant the computer was immediately usable after power-on, without needing disks or tapes.
Even today the Model 100 remains admired for its elegant design, reliability, and simplicity—qualities that helped shape the future direction of portable computing.
One group that embraced the Model 100 in particular was journalists. Reporters could write articles on the machine and transmit them over the built-in 300-baud modem, often sending stories directly from hotel rooms or press locations to their newsroom.
Another reason the Model 100 stood out was its ROM-based software environment. Programs such as the TEXT editor, BASIC interpreter, and telecommunications software were built directly into the machine. This meant the computer was immediately usable after power-on, without needing disks or tapes.
Even today the Model 100 remains admired for its elegant design, reliability, and simplicity—qualities that helped shape the future direction of portable computing.
Technical specifications
| Specification | Details |
|---|---|
| Processor | Intel 80C85 compatible CPU |
| Clock speed | 2.4 MHz |
| Memory | 8 KB, 24 KB, or 32 KB RAM |
| Display | 240 × 64 pixel LCD (8 lines × 40 characters) |
| Storage | RAM storage with optional cassette interface |
| Communications | Built-in 300 baud modem and RS-232 serial port |
| Power | 4 × AA batteries or external power supply |
| ROM software | TEXT editor, BASIC interpreter, TELCOM, Address book |
Collection status
| Collection status | Details |
|---|---|
| Condition | Good cosmetic condition |
| Keyboard | Full-travel portable keyboard |
| Display | LCD screen |
| Collection notes | Classic portable computer used by journalists in the 1980s |
| Collection state | Partially working (Display issue) |
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Magic smoke reportPASSED: The Model 100 did not produce smoke. The computer will need some work on the LCD though...
Power on tip: Make sure the polarity on the plug is correct, using AA batteries is advised. |
anchor: modeltwohunderd
TRS-80 Model 200
The style of the model 200 is amazing! This, like the Model 100, is a machine I managed to find for a lovely price. Well, I guess if you're a collector you tend to think most prices are nice, but for 25 bucks I really want to call this working Model 200 a steal. Just like its smaller sibling it runs on four AA batteries and springs to life almost instantly when powered on. That instant-on behaviour is one of the things that makes these machines feel surprisingly modern.
The Model 200 was introduced by Tandy in 1984 as the successor to the hugely successful Model 100 portable computer. At first glance the two machines look quite similar, but the Model 200 refined the concept with a larger screen and expanded capabilities. Mine even came with the disk drive, which makes it an even more interesting little system to explore and a nice addition to the collection. Why the model 200 mattersThe Model 200 represents an interesting moment in the evolution of portable computing. The earlier Model 100 had already proven that a truly portable computer could exist: battery powered, compact and ready to use instantly. The Model 200 built on that idea and pushed it a little further toward what we would later recognize as the laptop form factor.
One of the most noticeable changes is the larger flip-up display, which shows 16 lines of text instead of the 8 lines found on the Model 100. This made the machine far more comfortable for writing and editing text, something that was particularly appreciated by journalists who famously used these machines in the field to write and transmit stories over the built-in modem. |
Released in
1900
System Overview
|
Under the hood the Model 200 still uses the Intel 80C85 processor and the familiar Microsoft BASIC environment stored in ROM, keeping the instant-on behaviour and excellent battery life that made the Model 100 so popular. The machine also supported expansion through external peripherals such as the Tandy disk drive, allowing it to grow beyond the limitations of cassette storage.
Because of this combination of portability, usability and practical features, the Model 200 stands as one of the final and most refined members of the famous Model 100 family — a line of machines that demonstrated how powerful a truly portable computer could be long before modern laptops became common.
Because of this combination of portability, usability and practical features, the Model 200 stands as one of the final and most refined members of the famous Model 100 family — a line of machines that demonstrated how powerful a truly portable computer could be long before modern laptops became common.
Technical specifications
| Specification | Details |
|---|---|
| Processor | Intel 80C85A |
| Clock speed | 2.4 MHz |
| Memory | 24 KB RAM standard (expandable) |
| Display | LCD screen, 40 columns × 16 lines |
| Graphics | 240 × 128 pixels |
| Storage | Cassette interface and optional floppy disk drive |
| Power | 4 AA batteries or external power adapter |
| Built-in software | Microsoft BASIC, text editor, address book, terminal and Multiplan |
Collection status
| Collection status | Details |
|---|---|
| Condition | Working |
| Purchase | Bought for 25 bucks |
| Power | Runs on 4 AA batteries |
| Peripherals | Includes the external floppy disk drive |
| Collection notes | A great bargain and a nice companion to the Model 100 in the collection |
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Magic smoke reportPASSED: The model 200 did not produce any smoke.
Warning: the model 200 has a Varta battery inside the case make sure to remove this, as it might cause damage from leaking. |
anchor: pceen
TRS-80 PC-1
Imagine having this in your pocket back in the day! Initially this little machine was introduced simply as the TRS-80 Pocket Computer, but it was quickly renamed the TRS-80 Pocket Computer PC-1 once additional models appeared in the lineup. The PC-1 was sold by Radio Shack starting in 1980 and represents one of the earliest truly pocket-sized programmable computers available to hobbyists.
The machine itself is actually a rebadged Sharp PC-1211, something that was fairly common at the time as Tandy often partnered with Japanese manufacturers for their portable devices. I also happen to have the Sharp PC-1211 in my collection, which makes it fun to compare the two versions side by side. Despite its calculator-like appearance, the PC-1 is a fully programmable computer capable of running BASIC programs and storing small applications. One thing these machines are known for however is a common display problem where the LCD can start to fog up or appear to rot over time. Fortunately this issue is often repairable by carefully restoring the display layers. |
Released in
1900
System Overview
|
Why the PC-1 matters
The TRS-80 PC-1 sits at a fascinating point in the history of personal computing. In 1980 most computers were still relatively large desktop systems, yet the PC-1 demonstrated that a programmable computer could be small enough to carry in a pocket.
These early pocket computers blurred the line between programmable calculators and full computers. Machines like the PC-1 introduced many people to programming through compact and relatively affordable hardware. Using built-in BASIC, owners could write small programs, perform calculations, or store simple data while on the go.
The PC-1 also highlights the close relationship between Radio Shack and Sharp during the early 1980s. While sold under the TRS-80 brand in North America, the hardware itself came from Sharp, which was pioneering pocket-sized BASIC computers at the time. This collaboration helped spread these devices to a much wider audience.
Today the PC-1 stands as an early ancestor of portable computing — a tiny BASIC computer that predates laptops, handhelds and even many home computers, yet already shows the idea of having a programmable machine you can carry with you everywhere.
These early pocket computers blurred the line between programmable calculators and full computers. Machines like the PC-1 introduced many people to programming through compact and relatively affordable hardware. Using built-in BASIC, owners could write small programs, perform calculations, or store simple data while on the go.
The PC-1 also highlights the close relationship between Radio Shack and Sharp during the early 1980s. While sold under the TRS-80 brand in North America, the hardware itself came from Sharp, which was pioneering pocket-sized BASIC computers at the time. This collaboration helped spread these devices to a much wider audience.
Today the PC-1 stands as an early ancestor of portable computing — a tiny BASIC computer that predates laptops, handhelds and even many home computers, yet already shows the idea of having a programmable machine you can carry with you everywhere.
Technical specifications
| Specification | Details |
|---|---|
| CPU | Sharp SC43177 |
| Program memory | 1424 steps |
| Display | 24 character LCD |
| Programming language | BASIC |
| Storage | Optional cassette interface |
| Printer support | Sharp CE-122 printer/cassette interface |
| Power | 2 × CR2032 batteries |
| Size | Pocket sized programmable computer |
Collection status
| Collection status | Details |
|---|---|
| Condition | LCD shows the typical fogging/rot issue common to these machines, a repairable problem |
| Collection note | Interesting to compare with the Sharp PC-1211 which is essentially the same machine |
| Related system | Sharp PC-1211 |
| Collection state | Part of the TRS-80 portable lineup |
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Magic smoke reportIn need of repair: The PC-1 did not produce any magic smoke, the display will need a repair though.
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anchor: pctwo
TRS-80 PC-2
The larger size of this pocket computer is so appealing The TRS-80 Pocket Computer PC-2 followed the earlier PC-1 and was sold by Radio Shack in the early 1980s as part of their growing line of portable programmable computers. Just like the PC-1, the PC-2 is actually a rebadged Sharp machine — in this case the Sharp PC-1500 — reflecting the close cooperation between Tandy and Sharp during this period.
While the PC-1 looked very much like a programmable calculator, the PC-2 feels far more like a tiny computer. One of the first things you notice when holding it is that it is almost twice as thick as the PC-1, giving it a much more substantial feel. That extra space inside the case allowed Sharp to add more memory, a more capable processor and improved expansion possibilities. The PC-2 also introduces a more flexible BASIC environment and was often used together with peripherals such as cassette interfaces and small printers, turning this pocket machine into a surprisingly capable portable computer system. |
Released in
1900
System Overview
|
Why the PC-2 matters
The PC-2 represents the next evolutionary step in pocket computers. Where the earlier PC-1 blurred the line between calculator and computer, the PC-2 clearly moves into the territory of a fully programmable handheld system.
The machine is based on the Sharp PC-1500 platform, which became one of the most successful pocket computers of the early 1980s. Compared to earlier models it introduced more memory, a larger display and a significantly more powerful BASIC environment.
Another interesting aspect is the expansion ecosystem. The PC-2 could be connected to devices such as cassette interfaces and small thermal printers, allowing programs and data to be stored externally. This made it possible to build surprisingly complex applications on a device that still fit comfortably in a jacket pocket.
Today machines like the PC-2 illustrate how manufacturers experimented with portable computing long before laptops or PDAs existed, creating compact systems that could be programmed, expanded and carried almost anywhere.
The machine is based on the Sharp PC-1500 platform, which became one of the most successful pocket computers of the early 1980s. Compared to earlier models it introduced more memory, a larger display and a significantly more powerful BASIC environment.
Another interesting aspect is the expansion ecosystem. The PC-2 could be connected to devices such as cassette interfaces and small thermal printers, allowing programs and data to be stored externally. This made it possible to build surprisingly complex applications on a device that still fit comfortably in a jacket pocket.
Today machines like the PC-2 illustrate how manufacturers experimented with portable computing long before laptops or PDAs existed, creating compact systems that could be programmed, expanded and carried almost anywhere.
Technical specifications
| Specification | Details |
|---|---|
| CPU | Sharp LH5801 |
| Clock speed | Approx. 1.3 MHz |
| RAM | 3.5 KB standard |
| Display | 26 character LCD |
| Programming language | Sharp BASIC |
| Storage | Optional cassette interface |
| Printer support | Sharp CE-150 printer/cassette interface |
| Power | 4 × AAA batteries |
Collection status
| Collection status | Details |
|---|---|
| Condition | Working |
| Design note | Almost twice as thick as the earlier PC-1 |
| Related system | Sharp PC-1500 |
| Collection note | Part of the TRS-80 pocket computer lineup |
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Magic smoke reportPASSED: the PC-2 works great
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anchor: pcthree
anchor: mctien
TRS-80 PC-3
The PC-3 is a lovely little machine Where the PC-2 was almost twice the thickness of the PC-1, the PC-3 goes in the completely opposite direction. This little machine is the smallest of the bunch, being very thin and compact, making it feel much closer to a pocket calculator than the chunkier PC-2.
Just like the earlier TRS-80 pocket computers, the PC-3 is again a rebadged Sharp machine — this time the Sharp PC-1251. Radio Shack sold it as part of their growing line of handheld programmable computers in the mid-1980s. Despite its very small size the PC-3 is still a fully programmable BASIC computer. Programs can be written directly on the built-in keyboard and stored in memory, turning this tiny device into a surprisingly capable portable computer. |
Released in
1900
System Overview
|
Why the PC-3 matters
The PC-3 shows how quickly pocket computers evolved during the early 1980s. After the thicker and more powerful PC-2, manufacturers started pushing miniaturization again, making machines that were easier to carry while still offering programmable BASIC environments.
Based on the Sharp PC-1251 platform, the PC-3 combines a thin design with improved memory and a clearer display compared to the earliest pocket computers. While still very much a handheld system, it offered enough capability for small programs, calculations and simple data storage.
Like other Sharp-based pocket computers it could also connect to peripherals such as cassette interfaces and small printers, allowing programs to be saved externally.
Machines like the PC-3 highlight an interesting era where companies experimented with truly pocket-sized computers, long before smartphones or handheld PDAs existed. They offered programming and computing power in a form factor that could easily fit in a jacket pocket.
Based on the Sharp PC-1251 platform, the PC-3 combines a thin design with improved memory and a clearer display compared to the earliest pocket computers. While still very much a handheld system, it offered enough capability for small programs, calculations and simple data storage.
Like other Sharp-based pocket computers it could also connect to peripherals such as cassette interfaces and small printers, allowing programs to be saved externally.
Machines like the PC-3 highlight an interesting era where companies experimented with truly pocket-sized computers, long before smartphones or handheld PDAs existed. They offered programming and computing power in a form factor that could easily fit in a jacket pocket.
Technical specifications
| Specification | Details |
|---|---|
| CPU | Sharp SC61860 |
| Clock speed | Approx. 768 kHz |
| RAM | 4 KB |
| Display | 24 character LCD |
| Programming language | Sharp BASIC |
| Storage | Optional cassette interface |
| Printer support | Sharp CE-126P printer/cassette interface |
| Power | 2 × CR2032 batteries |
Collection status
| Collection status | Details |
|---|---|
| Condition | Working |
| Design note | Very thin and compact compared to the thicker PC-2 |
| Related system | Sharp PC-1251 |
| Collection note | Part of the TRS-80 pocket computer lineup |
Check out the Adventures in Archiving episode the PC-3 featured in here.
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Magic smoke reportPASSED: the PC-3 works and did not produce any smoke.
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anchor: duizendex
TRS-80 MC10
When I saw a MC10 at the Home Computer Museum I had to have one! After seeing this computer at the Home Computer Museum in Helmond, I knew I had to have it. So, when I found it on eBay, I made the purchase. It was shipped all the way from the United States, making it the first computer from the USA in my collection. However, connecting it to a television using NTSC RF proved to be a bit trickier.
This particular MC-10 had quite an adventurous journey. The delivery service left the package in my front yard without notice, meaning the computer spent an entire night outside in the rain before I discovered it the next morning. The computer has already appeared in a couple of videos, which you can find under the Appearances tab. |
Released in
1900
System Overview
|
Why the MC-10 matters
Released in 1983, the TRS-80 MC-10 (Micro Color Computer) was Tandy/Radio Shack’s attempt to create a very low-cost entry into home computing. It was positioned as a budget alternative to the better-known TRS-80 Color Computer (CoCo).
To keep the price low, the MC-10 was built around the Motorola MC6803 microprocessor and shipped with only 4 KB of RAM, which limited the complexity of programs it could run. BASIC was included in ROM, allowing users to immediately start writing programs once the system was connected to a television.
Unlike the larger Color Computer line, the MC-10 had a much more compact design and a small chiclet-style keyboard. It was primarily marketed toward beginners and families who wanted an affordable way to explore computing.
Although the machine had a relatively short life and limited software library, it remains an interesting example of the early-1980s race to produce ever cheaper home computers. Today the MC-10 is appreciated by collectors as a quirky member of the TRS-80 family and as one of the most compact systems produced by Radio Shack.
To keep the price low, the MC-10 was built around the Motorola MC6803 microprocessor and shipped with only 4 KB of RAM, which limited the complexity of programs it could run. BASIC was included in ROM, allowing users to immediately start writing programs once the system was connected to a television.
Unlike the larger Color Computer line, the MC-10 had a much more compact design and a small chiclet-style keyboard. It was primarily marketed toward beginners and families who wanted an affordable way to explore computing.
Although the machine had a relatively short life and limited software library, it remains an interesting example of the early-1980s race to produce ever cheaper home computers. Today the MC-10 is appreciated by collectors as a quirky member of the TRS-80 family and as one of the most compact systems produced by Radio Shack.
Technical specifications
| Specification | Details |
|---|---|
| Processor | Motorola MC6803 |
| Clock speed | 0.89 MHz |
| Memory | 4 KB RAM (expandable) |
| ROM | Microsoft BASIC in ROM |
| Graphics | Up to 128×96 graphics with 8 colors |
| Sound | Simple single-channel sound |
| Storage | Cassette interface |
| Video output | RF output for television |
| Release year | 1983 |
Collection status
| Collection status | Details |
|---|---|
| Origin | Purchased on eBay and shipped from the United States |
| Video output | Uses NTSC RF, making it slightly tricky to connect to European televisions |
| Collection notes | First computer from the United States in the RetroMels collection |
| Collection state | Semi-Working RF Modulator issue |
My Dutch MC-10 came with some basic programs you can find below.
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Magic smoke reportPASSED: The MC-10 did not produce any magic smoke!
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anchor: cocotwo
Tandy 1000 EX
The keyboard on this computer is particularly nice! This computer came into my collection when it appeared during my daily search for vintage computers on the Dutch version of eBay. Fortunately I was able to pick it up, and it turned out to be a really lovely machine.
Because I am always dealing with an eternal lack of space, I particularly appreciate computers with a small form factor, and the Tandy 1000 EX fits that role very nicely. Despite its compact size it still feels like a complete and capable system. The keycaps had yellowed quite a bit, so I retrobrighted them using a sous vide stick, which worked surprisingly well and brought them back much closer to their original color. Why the 1000 EX mattersReleased in 1986, the Tandy 1000 EX was part of the broader Tandy 1000 family, a line of IBM PC–compatible computers designed for home users.
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Released in
1900
System Overview
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What made the Tandy systems interesting was that they combined IBM PC compatibility with built-in enhancements, particularly improved graphics and sound capabilities compared to early PC hardware. The machines supported Tandy graphics modes, which allowed higher color graphics than the standard IBM CGA modes, making them especially attractive for games and educational software.
The EX model also represented a shift toward compact home-friendly designs, integrating the computer and keyboard into a single unit. Storage was handled by 3.5-inch floppy drives, which were becoming more common by the mid-1980s, and the system supported plug-in expansion through side-mounted slots.
Because of their strong game compatibility and enhanced graphics and sound, the Tandy 1000 series became one of the most popular alternatives to the standard IBM PC in the home market during the second half of the 1980s.
The EX model also represented a shift toward compact home-friendly designs, integrating the computer and keyboard into a single unit. Storage was handled by 3.5-inch floppy drives, which were becoming more common by the mid-1980s, and the system supported plug-in expansion through side-mounted slots.
Because of their strong game compatibility and enhanced graphics and sound, the Tandy 1000 series became one of the most popular alternatives to the standard IBM PC in the home market during the second half of the 1980s.
Technical specifications
| Specification | Details |
|---|---|
| Processor | Intel 8088 compatible CPU |
| Clock speed | 4.77 MHz |
| Memory | 256 KB RAM standard (expandable) |
| Graphics | Tandy graphics (enhanced CGA compatible) |
| Sound | 3-voice SN76496 sound chip |
| Storage | 5.25-inch floppy disk drive |
| Expansion | Side-mounted expansion slots |
Collection status
| Collection status | Details |
|---|---|
| Condition | Good cosmetic condition |
| Acquisition | Purchased through a Dutch eBay listing |
| Form factor | Compact all-in-one style design |
| Restoration | Keycaps retrobrighted using a sous vide stick |
| Collection state | Working |
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Magic smoke reportPASSED: The Tandy 1000EX did not produce magic smoke.
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anchor: cocotwotwo
TRS-80 Colour Computer 2
My first colour computer. I finally found one — and for a nice price.
While visiting the Home Computer Museum in Helmond, I set myself the goal for 2023 to add a Colour Computer to my collection. Not long after, this machine appeared and I was able to bring it home. Interestingly, this CoCo 2 actually became my first Color Computer, arriving before the CoCo 1 that I had originally been searching for. This particular unit has the well-known “melted keys” keyboard, a design that gives the machine a very distinctive look. Despite its unusual appearance, the keyboard works surprisingly well and fits the playful character of the system. Another fun detail is that this computer came from the same home as my Commodore 128D, making it a nice small connection between two very different computer families in the collection. |
Released in
1900
System Overview
|
Why the colour computer 2 matters
Released in 1983, the TRS-80 Color Computer 2 refined the original Color Computer design while keeping the same architecture and software compatibility.
The most noticeable change was the new case design, replacing the silver wedge-shaped enclosure of the original CoCo with a smaller and more modern looking beige case. Many models also featured the distinctive “melted” keyboard, where the keycaps appear to flow into each other as part of the molded design.
Internally, the machine kept the powerful Motorola 6809E processor and the MC6847 video chip, but later revisions improved reliability and memory configurations. Many systems shipped with larger RAM configurations, and the hardware revisions made the platform easier to expand with disk drives, cartridges, and other peripherals.
Because it remained fully compatible with the earlier machine while being cheaper and more widely available, the CoCo 2 became one of the most common models in the Color Computer line, helping to expand the platform’s user base during the mid-1980s.
The most noticeable change was the new case design, replacing the silver wedge-shaped enclosure of the original CoCo with a smaller and more modern looking beige case. Many models also featured the distinctive “melted” keyboard, where the keycaps appear to flow into each other as part of the molded design.
Internally, the machine kept the powerful Motorola 6809E processor and the MC6847 video chip, but later revisions improved reliability and memory configurations. Many systems shipped with larger RAM configurations, and the hardware revisions made the platform easier to expand with disk drives, cartridges, and other peripherals.
Because it remained fully compatible with the earlier machine while being cheaper and more widely available, the CoCo 2 became one of the most common models in the Color Computer line, helping to expand the platform’s user base during the mid-1980s.
Technical specifications
| Specification | Details |
|---|---|
| Processor | Motorola 6809E |
| Clock speed | 0.89 MHz |
| Memory | Typically 16 KB or 64 KB RAM |
| Graphics | Motorola MC6847 Video Display Generator |
| Display output | RF television output |
| Sound | Single-bit DAC audio |
| Storage | Cassette tape, floppy disk drives via expansion |
| Expansion | Cartridge slot and external expansion interface |
Collection status
| Collection status | Details |
|---|---|
| Condition | Good cosmetic condition |
| Keyboard | “Melted keys” keyboard variant |
| Origin | Came from the same home as my Commodore 128D |
| Collection notes | First Color Computer added to the collection |
| Collection state | Working |
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Magic smoke reportPASSED: The colour computer didn't produce smoke.
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TRS-80 Colour Computer
The COCO is a lovely machine! I really love the look of the silver painted case on this computer. When I first got it, I expected the keyboard to be a bit difficult to use, but it actually turns out to be surprisingly decent.
Over time I have really come to appreciate this line of machines. The TRS-80 Color Computer, often simply called the CoCo, is a fun and approachable system that feels very immediate to use. It boots quickly, BASIC is always ready, and experimenting with programs or loading software is straightforward. Because of that, I’ve started to enjoy the platform more and more. I am seriously considering getting an SD card storage solution for the system. Unfortunately those modern storage devices tend to be fairly expensive and difficult to find, which makes them a bit of a hunt in their own right. Why the colour computer mattersIntroduced in 1980, the TRS-80 Color Computer was designed by Tandy as an affordable home computer that could be sold through the company’s large network of Radio Shack stores. This wide retail presence helped the system reach a broad audience of hobbyists, students, and families.
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Released in
1900
System Overview
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One of the most interesting aspects of the machine is its Motorola 6809 processor, which was considered a very capable and elegant CPU for its time. Combined with the Motorola MC6847 video chip, the system provided color graphics and a flexible programming environment that made it popular for learning BASIC, experimenting with assembly language, and creating games.
The Color Computer also developed a very dedicated enthusiast community, with magazines, user groups, and hobbyists continuing to support the platform long after its commercial lifespan ended. Because of that strong community and the approachable design of the machine, the CoCo remains a well-loved system in the retro-computing world today.
The Color Computer also developed a very dedicated enthusiast community, with magazines, user groups, and hobbyists continuing to support the platform long after its commercial lifespan ended. Because of that strong community and the approachable design of the machine, the CoCo remains a well-loved system in the retro-computing world today.
Technical specifications
| Specification | Details | Source |
|---|---|---|
| Processor | Motorola 6809E | [1] |
| Clock speed | 0.89 MHz | [1] |
| Memory | 4 KB – 64 KB RAM depending on configuration | [1] |
| Graphics | Motorola MC6847 Video Display Generator | [1] |
| Display output | RF television output | [1] |
| Sound | Single-bit audio via DAC | [1] |
| Storage | Cassette tape and floppy disk drives | [1] |
| Expansion | Cartridge port and external expansion interface | [1] |
[1] TRS-80 Color Computer technical reference — trs-80.com reference archive
Collection status
| Collection status | Details |
|---|---|
| Condition | Good cosmetic condition |
| Case | Distinctive silver painted enclosure |
| Keyboard | Better than expected usability |
| Collection state | Working |
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Magic smoke reportPASSED: The colour computer didn't produce smoke.
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anchor: modelthree
TRS-80 Model 4
Badged: NPC 8000 Computer System II I always thought this was a Model III TRS-80 shout out to Michael for kindly pointing this out to me!
This TRS-80 Model 4 has an unusual origin story. I purchased the computer after stumbling upon it in the inventory of a closed-down pharmacy. Among boxes of surplus landline telephones sat this machine, listed under the name “NPC 8000 Computer System II.” Curious about it, I contacted the seller and asked if they were willing to sell the computer separately from the rest of the equipment. Fortunately they agreed, and the system eventually made its way into my collection. Although the badge on the front says NPC 8000 Computer System II, the machine itself is in fact a Radio Shack TRS-80 Model 4, one of the most recognizable all-in-one computers of the early 1980s. The computer powers up and works, but before I put it into regular use it will need a replacement filter capacitor in the power supply. Once that is addressed I am very excited to start loading and exploring many of the TRS-80 cassette tapes I have been collecting recently. |
Released in
1900
System Overview
|
Why the Model 4 matters
Released in 1983, the TRS-80 Model 4 was the direct successor to the TRS-80 Model III, refining and extending the all-in-one concept into a far more capable system. It improved performance, expanded memory, and introduced a high-resolution display mode, while maintaining compatibility with earlier software.
Like many systems of the era, it combined:
The Model 4 became especially popular in business and professional environments, as well as in education. Thanks to its support for TRSDOS 6 (LS-DOS) and CP/M, it could run a wide range of serious applications, from word processing to accounting software, alongside the large existing library of Model III programs.
A key strength of the system was its backward compatibility. With a hardware/software switch, it could operate in a Model III-compatible mode, allowing users to continue using older software while benefiting from the Model 4’s enhanced capabilities.
Interestingly, some systems were re-branded or sold under different labels in various markets, which explains why machines like this one sometimes appear with unexpected front badges such as the NPC 8000 marking.
Today, the Model 4 represents one of the most refined expressions of the all-in-one Z80-based microcomputer: a bridge between hobbyist machines and more serious business systems, and a clear evolution of the design philosophy seen in earlier systems like the TRS-80 Model I and Model III.
Like many systems of the era, it combined:
- a 12-inch monochrome CRT monitor
- a full-size keyboard
- built-in floppy disk drives (with cassette support largely phased out)
All in a single, integrated unit.
The Model 4 became especially popular in business and professional environments, as well as in education. Thanks to its support for TRSDOS 6 (LS-DOS) and CP/M, it could run a wide range of serious applications, from word processing to accounting software, alongside the large existing library of Model III programs.
A key strength of the system was its backward compatibility. With a hardware/software switch, it could operate in a Model III-compatible mode, allowing users to continue using older software while benefiting from the Model 4’s enhanced capabilities.
Interestingly, some systems were re-branded or sold under different labels in various markets, which explains why machines like this one sometimes appear with unexpected front badges such as the NPC 8000 marking.
Today, the Model 4 represents one of the most refined expressions of the all-in-one Z80-based microcomputer: a bridge between hobbyist machines and more serious business systems, and a clear evolution of the design philosophy seen in earlier systems like the TRS-80 Model I and Model III.
Technical specifications
| Specification | Details | Source |
|---|---|---|
| Processor | Zilog Z80A | [1] |
| Clock speed | 4 MHz (switchable to 2 MHz Model III compatibility mode) | [1] |
| Memory | 64 KB standard, expandable to 128 KB | [1] |
| Display | Integrated 12-inch monochrome CRT (green or white phosphor) | [1] |
| Text resolution | 64 × 16 or 80 × 24 characters (high-resolution mode) | [1] |
| Storage | Single- or double-sided 5.25" floppy drives (typically 180 KB to 360 KB per disk) | [1] |
| Operating system | TRSDOS 6 (LS-DOS), Model III TRSDOS compatibility mode | [1] |
| Keyboard | Full-travel keyboard with numeric keypad | [1] |
| Notable feature | Backward compatibility with Model III software via hardware/software switch | [1] |
| Known issue | RIFA line filter capacitors prone to failure and should be replaced | Common restoration issue |
[1] TRS-80 Model 4 technical specifications — trs-80.com reference archive
Collection status
| Collection status | Details |
|---|---|
| Condition | Good cosmetic condition |
| Origin | Found in the inventory of a closed-down pharmacy |
| Acquisition | Purchased separately after contacting the seller |
| Front badge | NPC 8000 Computer System II |
| Identification | Radio Shack TRS-80 Model III |
| Collection state | Working |
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Magic smoke reportFailed: The Model IIII produced smoke off camera (non RiFa part)
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