portable

First steps with my Tandy TRS-80 Model 100

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I recently acquired a shiny Model 100 portable with necessary accessory. I played a bit with the machine before cleaning it and I was a bit surprised that it could retain data in the RAM disk for minutes after disconnecting the power. That gave me the impression that there was a backup battery inside, which scared me enough to open the machine immediately… and yes, although the battery still provided some voltage, it started destroying itself and the computer. I removed the residue from both the backup battery and the battery compartment for AA cells and cleaned the rest of the machine. It looks almost like new now.

I have to say that I am very impressed with the Model 100. The user experience is closer to professional computers of that time than home 8-bit machines. The programs in ROM can read/write the same files, switching between them is fast and there is even a shared clipboard. I particularly like the built-in terminal emulator with handy access to download/upload features and easy configuration. This was a true mobile companion for those working on the road and accessing the company minicomputer over modem.

My version does not have the modem, but at least the null-modem communication works flawlessly. I think I should install an old UNIX somewhere and try accessing it like in the old days. Somebody even created a Model 100 termcap definition file, so it is possible to use control functions of its terminal emulator in UNIX.

TRS-80 Model 100 Acquisition

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A guy contacted me that he found a complete TRS-80 Model 100 at the recycling center, ready to be destroyed. He was not a vintage computer collector but realized that it could have value for some, so he started to google somebody who can appreciate it and found my Czech blog. He wrote me a message that I could take it for free if I was interested.

… and I indeed was. This particular machine travelled to our country during the socialism era and it is quite rare here. I love portable computers of all kinds, so I am very curious to see whether this 1983 ultra-mobile machine was just a useless toy or a valuable companion on the road. The next step is to clean everything. The original suitcase started to disintegrate, and everything is covered with the black filth.

Apple IIc As a Battery-Powered Portable Computer

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Apple IIc was designed to be portable. That meant that the computer could be easily carried from work to home or anywhere else where you had a power socket and a composite screen (or TV). I knew about the LCD option offered by Apple but I didn’t know that there were complete kits to make the computer usable everywhere.

A true mobile user could enhance his Apple IIc with a passive-matrix non-backlit LCD (connected to the video port using a ribbon cable) and an external lead acid battery. There were also bags specially designed to carry all this stuff safely.

This option was not very successful, though. Not because of its weight around five kilograms – that was adequate by the standards of the era (there were people carrying Osbornes). The main problem was the LCD screen which could produce a good picture only under direct sun light. The contrast was extremely low and the screen was hardly readable in a dimly lit room. I’ve tried few different laptop LCD screens from the same generation and my eyes almost bled after 30 minutes of work.

Having three separate parts was also not very convenient for frequent travelers. The screen was not designed to cover the keyboard when the computer was being transported and you always had to attach the battery. The first generation of laptops started to appear at the same time. Although they were as heavy as this kit, they had all components in a single briefcase-like package. In 1985, you could buy Bondwell Model 2 (a cheaper CP/M laptop with 64kB of memory) or one of those PC compatible laptops which started to appear at the end of the year (like my Bondwell Model 8).

Image sources: imgur.com, popcorn.cx

Olivetti Quaderno (PT-XT-20)

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This little machine is a very interesting piece of engineering. It is an XT compatible (four times faster than original XT) and there is a standard 2,5” hard drive inside. Unfortunately it is hard to find any Quaderno in a working condition. Main problems are dead hard drives, bad capacitors and leaked batteries. I was given this one from an old guy who bought it new and had been using it for years in 90s. It was fully working when it was put in a box twenty years ago, but now we are unable to power it on and it looks completely dead.

We disassembled it to see what happened. The problem is probably in capacitors as there is some leakage around few of them. Backup battery was not leaked and fuses seem ok as well so I believe that we will manage to fix the unit.