Autopsy:

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from Wikipedia:

TRS-80 was Tandy Corporation’s desktop microcomputer model line, sold through Tandy’s Radio Shack stores in the late 1970s and early 1980s, and one of the earliest mass-produced personal computers. The first units, ordered unseen, were delivered in November 1977, and rolled out to the stores the third week of December.

The line won popularity with hobbyists, home users, and small-businesses. Tandy Corporation’s leading position in what Byte Magazine called the “1977 Trinity” (Apple, Commodore and Tandy) had much to do with Tandy’s retailing the computer through more than 3,000 of its Radio Shack storefronts. Notable features of the original TRS-80 included its full-stroke QWERTY keyboard, small size, its floating point BASIC programming language, an included monitor, and a starting price of $600.

The pre-release price was $500 and a $50 deposit was required, with a money back guarantee at time of delivery. One major drawback of the original system was the massive RF interference it caused in surrounding electronics. Stricter FCC regulations on interference led to the Model I’s replacement by the Model III.

Radio Shack announced the TRS-80 (Tandy Radio Shack) at a New York City press conference on August 3, 1977. It cost $399, or $599 with a 12″ monitor and a Radio Shack tape recorder as datacassette storage. Before this, the most expensive product Radio Shack sold was a $500 stereo.

The company hoped that the new computer would help Radio Shack move into higher-priced products, and improve its “schlocky” image among customers. Small businesses were the primary target market, followed by education, then consumers and hobbyists. Despite its hobbyist customer base, Radio Shack saw hobbyists as “not the mainstream of the business”. Although the press conference did not receive much media attention due to a terrorist bombing elsewhere in the city that day, “six sacks of mail” arrived at company headquarters asking about the computer, and over 15,000 people called Tandy to purchase a TRS-80, paralyzing its switchboard.

Unlike competitor Commodore—which had announced its PET several months earlier but had not yet shipped any—Radio Shack began shipping computers by September. Still forecasting 3,000 sales a year, the company sold over 10,000 TRS-80s Model Is in its first one and a half months of sales, and over 200,000 during the product’s lifetime.

source: wikipedia

I have received this computer Commodore CBM 8296-D 1 year ago. The computer has never worked, it only displays a black screen without any sound beep at the startup boot.

The repair it was very simple, i have replaced the PLA IC 324745-01 (UE5) and 324744-01 (UE6) with two EPROM 27C512 70ns (suitably programmed). The Universal PLA adapter was kindly donated by Manosoft.

Download:

• PLA Rom 8296(D) (924)
• EDIT Rom 324243-02b (916)

Autopsy:

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The collection includes:

• Mattel (Radofin) Aquarius Home Computer System (boxed).
• Mattel (Radofin) Aquarius Mini Expander Module (boxed).
• Mattel (Radofin) Aquarius Game Cartridge Night Stalker (boxed).
• Mattel (Radofin) Aquarius 4k Memory Expansion (boxed).
• Mattel (Radofin) Aquarius Data Recorder (boxed).
• Mattel (Radofin) Aquarius Thermal Printer.

from Wikipedia homepage:

Aquarius is a home computer designed by Radofin and released by Mattel in 1983. It features a Zilog Z80 microprocessor, a rubber chiclet keyboard, 4K of RAM, and a subset of Microsoft BASIC in ROM. It connects to a television set and uses a cassette tape recorder for secondary data storage. A limited number of peripherals, such as a 40-column thermal printer, a 4-color printer/plotter, and a 300 baud modem, were released for the unit.

Looking to compete in the standalone computer market, Mattel Electronics turned to Radofin, the Hong Kong based manufacturer of their Intellivision consoles. Radofin had designed two computer systems. Internally they were known as “Checkers”, and the more sophisticated “Chess”. Mattel contracted for these to become the Aquarius and Aquarius II, respectively. Aquarius was announced in 1982 and finally released in June 1983, at a price of $160.

Production ceased four months later because of poor sales. Mattel paid Radofin to take back the marketing rights, and four other companies—CEZAR Industries, CRIMAC Inc., New Era Incentives, Inc., and Bentley Industries—also marketed the unit and accessories for it. Bentley Industries (of Los Angeles) and New Era Incentives, Inc. (of St. Paul) are still in business, though they no longer have any affiliation with the Aquarius product line.

source: wikipedia

Autopsy:

The photos of the inside can be found here.

from Wikipedia homepage:

The ZX81, released in a slightly modified form in the United States as the Timex Sinclair 1000, was a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair’s ZX80 and was designed to be a low-cost introduction to home computing for the general public. It was hugely successful and more than 1.5 million units were sold before it was eventually discontinued.

The ZX81 found commercial success in many other countries, notably the United States, where Timex manufactured and distributed it under licence and enjoyed a substantial but brief boom in sales. Timex later produced its own versions of the ZX81 for the US market – the Timex Sinclair 1000 and Timex Sinclair 1500. Unauthorised clones of the ZX81 were produced in a number of countries.

The ZX81 was designed to be small, simple, and above all cheap, using as few components as possible to keep the cost down. Video output was to a television set rather than a dedicated monitor. Programs and data were loaded and saved onto audio tape cassettes. It had only four silicon chips on board and a mere 1 kB of memory. The machine had no moving parts – not even a power switch – and used a touch-sensitive membrane keyboard for manual input.

The ZX81′s limitations prompted the emergence of a flourishing market in third-party peripherals to improve its capabilities. Such limitations, however, achieved Sinclair’s objective of keeping the cost of the machine as low as possible. Its distinctive design brought its designer, Rick Dickinson, a Design Council award.

The ZX81 could be bought by mail order in kit form or pre-assembled. In what was then a major innovation, it was the first cheap mass-market home computer that could be bought from high street stores, led by W.H. Smith and soon many other retailers. The ZX81 marked the first time that computing in Britain became an activity for the general public, rather than the preserve of businesspeople and electronics hobbyists. It inspired the creation of a huge community of enthusiasts, some of whom founded their own businesses producing software and hardware for the ZX81. Many went on to play a major role in the British computer industry in later years.

The ZX81′s commercial success made Sinclair Research one of Britain’s leading computer manufacturers and earned a fortune and an eventual knighthood for the company’s founder, Sir Clive Sinclair.

source: wikipedia

Sorry, this entry is only available in Italian.

I was very lucky in this repair, the fault is a broken belt that is used for the operation of the Floppy “Quick Disk”.

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I post some screenshots and a video of the repairing of a NEC PC-Engine LT console.

Defect in the console:

Some capacitors have leaked acid on the pcb, i had to clean with the right product made especially for cleaning the pcb before proceeding with the replacement operation. The LCD screen is was disassembled to remove the dirt inside.

Autopsy:

from Wikipedia homepage:

The Odyssey 2100 was released in 1978 and uses the same case design as the 2001. Using the National Semiconductor MM-57186N chip, the 2100 plays 6 games with multiple varitions: Wipe-Out (Breakout style, 7 variants), Flipper (7 variants), Tennis (2 variants), Handball (2 variants), Ice Hockey (2 variants), Football (3 variants).

The Magnavox Odyssey was a general brand name of the company’s complete line of home video game consoles released from 1972 through 1978. The line includes the original Magnavox Odyssey console, both Magnavox and Philips versions of the Odyssey series of dedicated video game consoles, and the Magnavox Odyssey² cartridge-based video game console released in 1978.

source: wikipedia

Commodore 64 in a good working state to use for spare parts.

Autopsy:

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from MyOldComputers.com:

The year was 1978. Atari was at the top of the video gamming world with its 2600 VCS game console. Atari management looked around and saw a new and potentially lucrative market just beginning to take shape. This market was the Home Computer Market. They saw a market with relatively few major competitors and Atari was in a great position to market a computer of their own. They, after all, were a trusted household name, everyone owned an Atari or knew someone who did!

So December of 1978 Atari introduced the 400 and 800 series computers. The actual computers were not delivered until late 1979 due to production problems. The 400 was a scaled down version of the Atari 800. Introduced as an entry level computer based on the same MOSTEK 6502A processor running at 1.70 MHz with 16K of user RAM built in. It had a membrane style keyboard (not very touch type friendly) with 62 touch sensitive keys and 4 special keys to the right of the keyboard.

It stood out amongst the other computer offerings of the day with its graphics and sound capabilities. It was capable of producing 128 colors on the screen using the CTIA video processor and up to 256 colors with the upgraded GTIA video processor chip used on later versions of the computer. The 400 was first amongst the early computers to be able to display 4 programmable screen objects simultaneously called ‘Player-missiles’ (also known as ‘Sprites’ on Commodore computers). This was at a time when the most computers produced only monochrome displays or very primitive 8 color screens. The graphics were handled by a custom chip called the “ANTIC” (CTIA/GTIA). This chip was designed to work as a sort of co-processor to take the work load away from the main processor to display graphics and color on the screen.

The team that developed the custom chips inside the 400 and 800 was headed by Jay Miner who later, after leaving Atari, headed the teams who developed the custom chips that surrounded the Motorola MC68000 processor that powered arguably the most advanced computer of its time, The Amiga 1000!

source: myoldcomputers.com

Autopsy:

This is a gift from my brother for my birthday.

from Wikipedia:

Congo Bongo (J: Tip Top (ティップタップ Tippu Tappu?)) is an isometric platform arcade game released by Sega in 1983. Strong evidence from analysis of the game’s ROM claim that Ikegami Tsushinki also did development work on Congo Bongo.

The game has come to be seen as Sega’s answer to the highly successful Donkey Kong game that was released two years prior. The player takes the role of a red-nosed safari hunter who tries to catch an ape named “Bongo”. The hunter seeks Bongo to exact revenge for an apparent practical joke in which Bongo set fire to the hunter’s tent, giving him a literal “hotfoot”. Game was named by Pete Gorrie who was the CFO at that time.

source: wikipedia

Autopsy:

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Thanks go to Andrea Pierdomenico for sending these two things in perfect condition and ‘seems’ never used.

from SharpMz.org:

The Quick Disk drive in terms of cost is was a more practical proposition for the home user. The drive is built into the computer for the MZ-700 and MZ-800 in place of the data recorder.

The Quick Disk allows you to load 64K of sequential data in 8 seconds, which is a vast improvement in performance compared to cassette tapes. However, the Quick Disk operates in a very similar way to cassette tapes in that data has to be accessed sequentially, rather than at random as is possible with the floppy drives.

A special Quick BASIC is supplied. However, perhaps the most interesting way of using the Quick Disk would be as a back-up store to the RAM file card, described in the next section, as this configuration would give a very effective system which was rapid in use, at reasonable cost.

source: sharpmz.org

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from Old-Computers.com:

The sharp MZ 800 was the successor of the MZ 780. It was partially compatible with the MZ 700 series and the old MZ 80K series as well.

It was sold under three reference numbers:

• MZ-811 without tape drive.
• MZ-821 with built-in 1200-baud tape drive.
• MZ-831 with tape drive and built-in 4-colour printer-plotter.

The Tape drive could be substituted for a Quick-disk drive unit. The Quick-Disc was a small 2.8-inch disk with sequential access.

Like the MZ 700, there was no language in ROM, it had to be loaded from tape, quick disk or floppy disk. The ROM only contained boot code, OS calls and special code to allow the user to use the 64 KB RAM as a virtual disk.

A single or double 5.25″ disk drive could be connected to the MZ 800. It then worked under a special version of CP/M called P-CP/M. Some great products like Wordstar, dBase II and Multiplan were adapted to it. Under CP/M, it was possible to read multiple disk formats from the 360 KB (Sharp format) to the 720 KB (CP/M IBM PC format).

The MZ 800 was sold in Japan under the name SHARP MZ 1500. The MZ 1500 had the same characteristics except its black case, a built-in Quick-Disc drive and a slighty different graphic video management.

source: old-computers.com

Autopsy:

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from MyOldComputers.com:

The year was 1978. Atari was at the top of the video gamming world with its 2600 VCS game console. Atari management looked around and saw a new and potentially lucrative market just beginning to take shape. This market was the Home Computer Market. They saw a market with relatively few major competitors and Atari was in a great position to market a computer of their own. They, after all, were a trusted household name, everyone owned an Atari or knew someone who did!

So December of 1978 Atari introduced the 400 and 800 series computers. The actual computers were not delivered until late 1979 due to production problems. The 400 was a scaled down version of the Atari 800. Introduced as an entry level computer based on the same MOSTEK 6502A processor running at 1.70 MHz with 16K of user RAM built in. It had a membrane style keyboard (not very touch type friendly) with 62 touch sensitive keys and 4 special keys to the right of the keyboard.

It stood out amongst the other computer offerings of the day with its graphics and sound capabilities. It was capable of producing 128 colors on the screen using the CTIA video processor and up to 256 colors with the upgraded GTIA video processor chip used on later versions of the computer. The 400 was first amongst the early computers to be able to display 4 programmable screen objects simultaneously called ‘Player-missiles’ (also known as ‘Sprites’ on Commodore computers). This was at a time when the most computers produced only monochrome displays or very primitive 8 color screens. The graphics were handled by a custom chip called the “ANTIC” (CTIA/GTIA). This chip was designed to work as a sort of co-processor to take the work load away from the main processor to display graphics and color on the screen.

The team that developed the custom chips inside the 400 and 800 was headed by Jay Miner who later, after leaving Atari, headed the teams who developed the custom chips that surrounded the Motorola MC68000 processor that powered arguably the most advanced computer of its time, The Amiga 1000!

source: myoldcomputers.com

This is a little description of the repair of a Radio Shack TRS-80 Model 1 for a Friend.

The computer comes with several problems.

• Some IC are dead or in shorted state.
• Keyboard flat cable.
• One key “L” is dead.

Finding the cause of the fault has not been easy, i had to ask for a help to Ian, this dude is an expert of TRS-80 repairs.

How you can see from the photos, i had to replace a number of IC.

• 4 x Video RAM 2102 (Z62 / Z63 / Z46 / Z48)
• 1 x Z80 (Z40)
• 1 X 74LS157 (Z31)
• 1 X 74LS93 (Z32)

Stage of the defect (before and after):

Keyboard repair (replacement of internal contacts):

Micro Computer Technical Reference Handbook:

Download: TRS-80 Micro Computer Technical Reference Handbook (2493)