Buyer’s Guide for the Commodore PET

By Mark from

Key Takeaways

  • The PET was one of the first mass-market home/personal computers, released by Commodore in 1977.
  • Came in multiple models like the classic PET 2001, upgrading from 8KB to 32KB of memory.
  • Used a 1MHz MOS 6502 CPU, had a built-in monochrome CRT monitor, and DAT cassette storage.
  • Prices range from $100-500+ depending on model, condition, and included peripherals.
  • Great for vintage computing fans who want an early Commodore system. Not as complex as building a kit computer.
  • Durability of these 40+ year old systems makes condition key. Confirm it powers on and loads programs properly.
  • Check for included components like manuals, cables, tapes, and the all-important external cassette deck.
  • Be prepared to recap the motherboard and deal with other aging components to restore full functionality.


The Commodore PET (Personal Electronic Transactor) line holds an important place in home computing history as one of the first all-in-one mass market personal computers when it launched in 1977. Pre-dating even the legendary Apple II by a year, the PET helped bring microcomputers into homes and small businesses beyond just electronics hobbyists. It cemented Commodore as a major early computing company.

With its integrated CRT monitor, full QWERTY keyboard, decent software library, and increasing affordability, the PET line was many people’s first experience using a desktop computer. Models ranged over the years from the original PET 2001 with 8KB of RAM up to the feature-rich 2001-N with 32KB.

For retro computing fans today, the PET provides a window into those pioneering early days of desktop systems. They’re quite collectible, but their age does mean maintenance, repair, and proper usage are key to enjoying these 40+ year old machines. This guide will cover what to look out for when purchasing a classic Commodore PET.

PET History and Background

Commodore emerged in the mid-1970s as major supplier of electronic calculators and digital watches. But company leaders saw potential in the nascent personal computer field, which at the time was dominated by expensive kits and microcomputer boards purchased primarily by electronics hobbyists.

Commodore acquired pioneering computer company MOS Technologies in 1976, giving it crucial chip manufacturing capabilities including the 6502 CPU. Engineers immediately began work on what would become the PET project. Essentially, their goal was to build an affordable, consumer-friendly desktop computer using MOS chips for both the CPU and other support components.

The result was the PET 2001, which launched at computer shows in late 1977. The all-in-one design contained a monochrome CRT monitor, full-sized membrane keyboard, CPU, RAM, and storage – complete right out of the box. It was still expensive at nearly $800, but an order of magnitude cheaper than hobbyist kits of the day.

Improved variants like the 2001-N and 2001-B rapidly followed over the next few years, increasing RAM, adding a second cassette drive, and enhancing the keyboard. The PET proved popular with schools, households, and small business owners who wanted access to computing without needing to build a kit or just use a ‘dumb’ terminal.

By 1981, Commodore began shifting focus to even more affordable successors like the legendary VIC-20 and Commodore 64. But the pioneering PET 2001 laid crucial groundwork and gave Commodore its first major success in the home computing market.

Models and Variants

Commodore released numerous incremental PET variants between 1977-1981:

  • PET 2001 – Initial 8KB model with monochrome monitor, CHR7040 cassette drive. 8KB RAM expandable to 32KB.
  • PET 2001-N – Added a 2nd cassette drive. Blue keys vs original black. Extra RAM standard.
  • PET 2001-B – Same as 2001-N but with upgraded BASIC 4.0 in ROM.
  • PET 3000 – UK/European models with slightly compact chassis. 4KB and 8KB RAM options.
  • PET 4000 – Business-focused PET with 80 column green screen monitor and 2nd IEEE-488 port. 16KB RAM.
  • PET 8000 – 79-key keyboard model. Built using newer chips for cost reduction. CBM8000 in Germany.
  • SuperPET – High end model focused on large business users, with more RAM, dual processors, SCSI, and CP/M OS.

The most common PET models available today are usually the 2001’s with varying RAM amounts up to 32KB. But it’s worth verifying the exact hardware and functional differences when looking to purchase.

What to Look For When Buying

Here are key items to inspect closely when evaluating a vintage Commodore PET 2001 for purchase:

Power Up Test – Confirm the PET successfully boots and runs through its startup memory test. Listen for any odd sounds from the CRT.

Screen Condition – Check for screen burn-in on the monochrome CRT monitor. There should be no distortion or discoloration.

Cassette Load – Verify programs can load properly from cassette using the external tape drive. Listen for any squealing or grinding noises.

Keyboard Issues – PET keyboards are notoriously fragile. Ensure all keys trigger properly without sticking. No missing keys either.

RAM Expansion – Open the case to check for any added RAM expansion cards or sockets. More than 32KB usually indicates upgrades.

Included Components – Look for original manuals, cables, cassette tapes, and especially the all-important external cassette drive needed for saving programs.

Accessory Ports – Inspect the rear ports for any damage or oxidation. Especially important is the proprietary CBM IEEE-488 port used with disk drives and printers.

Case Condition – Check for any cracks, yellowing, or physical damage on the outer case and keyboard. Screws should all be present.

A fully working PET capable of loading programs with its original cassette drive is ideal. Be prepared to do thorough cleaning, calibration, and component replacements like electrolytic capacitors to restore full functionality if issues arise.

Where to Buy a Commodore PET

Here are some good options for locating Commodore PET computers and accessories:

  • eBay – With patience, eBay provides the widest selection of PET models and replacement parts. Be wary of untested systems though.
  • Forums – Places like Lemon64 or Neo-Geo Forums often have members selling or trading PET computers and peripherals in their classified sections.
  • Local Listings – Check craigslist, Kijiji, or Facebook Marketplace for postings from vintage computing enthusiasts in your area looking to sell or trade PET items.
  • Retro Conventions – Events like Vintage Computer Festivals can be a great place to locate PET computers and accessories being sold or exhibited by collectors.
  • Commodore Repair Shops – Businesses like A-Vidd Design offer fully refurbished and tested Commodore systems for sale, though at higher cost. Provides peace of mind.

Be sure to factor in any taxes/import fees if buying internationally. Pay via safe methods and request insured shipping given the high value of original 40+ year old computing artifacts like the PET.

PET Pricing

Pricing for the Commodore PET can vary significantly based on condition, included accessories, RAM amounts, and more. Here are typical values:

  • PET 2001 – As low as $100-150 for non-working units up to $300-500+ for mint, fully functional systems with cassette drive.
  • PET 3000/4000 – Slightly less popular so tend to cost $50-100+ less than comparable 2001 models.
  • 8KB RAM Models – The early 8KB PETs often sell for $100-250 less than maxed out 32KB configurations.
  • Cassette Drive – Working external cassette drives alone can sell for $150-300. Complete with tapes can top $500 for rare titles. Absolutely essential purchase for saving programs.
  • Parts Systems – Non-functioning PETs with good cases and keyboards can still sell for $50-100 as donor parts sources.
  • SuperPETs – As one of the last and most advanced PET models, these often fetch over $1000 in working condition with full memory expansions.
  • Printers – Commodore printers range from $100-300+ depending on whether IEEE-488 interface is included and overall testing/condition.

It’s all about condition and included components – common models like the PET 2001 in average shape tend to cost less, while mint setups with all accessories and rarer variants have much higher collector value.

Is the PET Worth Buying?

For vintage computer enthusiasts, especially those with an interest in pioneering 1970’s systems, the Commodore PET is highly recommended both as a collector’s piece and functional computing device:

Historic Value – As one of the earliest all-in-one home computers, PET is hugely significant in the history of personal computing.

Strong Community – The PET enjoys an active community of owners sharing repairs, software, and restoration knowledge to keep these systems going.

Affordability – Condition aside, PET models are still quite affordable for their age compared to even more popular platforms like Apple II’s.

Education – PET’s simplified design compared to kits makes it great for learning about early computing and electronics repair.

Software Library – Thousands of titles released over its lifespan, including early games, business apps, BASIC programs and more to enjoy.

Upgradability – PET’s internal expansions slots and ports mean it’s very upgradeable with more RAM, disk drives, printers, and other functionality boosting options.

For Commodore fans or students of computing history, the pioneering PET is a cornerstone machine worth experiencing first-hand. Maintaining a 40+ year old computer does have challenges, but the active community makes it very achievable to keep these vintage systems running.

Frequently Asked Questions

Here are some common questions about purchasing and owning a Commodore PET.

Where can I find replacement parts?

eBay tends to have the widest assortment of repair parts like replacement keyboards, power supplies, and cassettes drives. Sites like also have salvaged parts.

What should I look for in the CRT condition?

Avoid any PET monitors with burned-in images, geometric distortion, color tinting, or convergence issues which likely indicates monitor repair will be needed.

How necessary is the cassette drive?

The external cassette drive is required for saving any custom programs or data. Working units with tapes are highly recommended, but audio cable workarounds are possible.

What cables and connections does the PET use?

Primarily the back has the power input, cassette ports, CH 310 video out, IEEE-488 port, and external cassette data port. Avoid corrosion here. PETs do not support HDMI output.

What maintenance is recommended?

Common suggestions are re-capping aging motherboards, cleaning/lubricating keyboards, cassette drive belt replacement, monitor tuning and calibration, and ensure no voltage leaks across modern power supplies.

What OS, software and languages does PET support?

Built-in ROM comes with BASIC v2 or v4 on newer models. Lots of code samples and early business programs available to run. 6502 assembly, Forth, LOGO, C compilers, and more also available.


As a pioneering all-in-one home computer that helped launch Commodore into mainstream success, the PET series holds a special place in personal computing history. Models like the classic PET 2001 and 4000 still evoke an exciting era of possibilities in that first decade of desktop systems aimed at average users.

While purchasing a 40+ year old PET today does come with some maintenance challenges, these systems were built quite durably for the time. With some basic upkeep and repairs, enjoying vintage PET computing is certainly within reach for dedicated retro fans willing to embrace a little hands-on restoration work.

Few devices transport you back to the dawn of home computing like powering on the boot screen of a PET 2001. Experiencing this pioneering Commodore machine first-hand is a great way to appreciate just how much advancement we’ve made in just four decades – and yet how foundational those early systems still remain.

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