New Article: Toshiba T3200SX

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I just wrapped up an article on the Toshiba T3200SX, a desktop-replacement laptop from 1989. This beauty boasts a 386(SX) CPU and a stunning VGA gas-plasma display.

You can check it out here:

For those of you who are new to the world of vintage computers, this article can provide some valuable context and perspective. I delved into why the 386 was such a crucial milestone for PCs and a few lesser-known details. I absolutely adore this machine. I don’t think I own any other portable  computer from the 80s that brings me as much joy while working on it. If  only it were just a tad lighter..

Olivetti Quaderno PT-XT-20 (1992) – part 2

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You might think that the machine is useless without a working HDD and no floppy drive, but that is not true. Quaderno has a small bootable “ROMDOS” drive with basic system files, COMMAND.COM, a RAMDISK driver (up to 320KB of EMS memory can be used and you still have full 640KB of conventional memory) and Interlink software. This drive is interesting, because it acts like a read-write one. You can edit config.sys and autoexec.bat (the changes are there even after shutdown, if the CMOS battery is ok or AC is connected). You can even copy files there, but if it’s more than a few KB, the system will crash hard (requiring you to
reinitialize the ROMDOS).

With Interlink, you can mount remote HDDs over a serial port. I used it to run VC (Volkov Commander) to edit the config.sys (no EDIT.COM in ROMDOS) and enable the RAMDISK driver. After this, I had my small but fast local storage (non-persistent) and everything bigger was started directly out of the remote HDD from another computer. This is a good way to test the computer before fixing the HDD or installing a flash/SRAM card in PCMCIA 1.0.

Olivetti Quaderno PT-XT-20 (1992) – part 1

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This little machine is an XT-class computer with 16MHz NEC V30HL, 1MB of RAM, double-CGA 640×400 graphics (AT&T6300/Toshiba compatible), MS-DOS in ROM and a 20MB Conner HDD (working in 8-bit mode). Its size and weight are halfway between regular laptops and handhelds (it is ultra-portable even by today’s standards). I got one three years ago and it was dead like almost all of them nowadays. The issue was “easily” fixable by replacing all the SMD capacitors. We replaced the ones on the logic board and the computer booted. However, the screen was not able to retain the contrast value, which made it hardly usable. Also the Conner drive had the head stuck (a common issue, that I want to fix later). We disassembled the lid and replaced a capacitor on the display board. Everything worked flawlessly when disassembled. As soon as we assembled the machine together, it stopped working. We were tired and put the whole thing into storage.

Recently, after three years, we gave the machine another chance. Disassembled it, booted and everything worked ok (except the HDD of course). After assembling it back? No sign of life… The issue was caused by too long legs on the new capacitor in the display board. The legs were sharp and went through the insulation layer on the (metalized) screen cover and shorted the capacitor (I know, shame on us…). Once we fixed this, we were able to put the machine back together and enjoy it. David also replaced cracked internal plastic parts using a 3D printer.

Now we have a trouble-free machine in a perfect shape with just one flaw – a faulty hard drive (and no floppy drive). However, that is not as big issue as one might think…

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.

Old CGA Laptops and Monochrome TV Output

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When I tried a composite video output on my Bondwell Model 8 for the first time I was disappointed that there were no colors in the picture. I searched over the internet and old reviews and found that the output is “monochrome only”.

Bondwell used the V6355 chip sold under Yamaha brand. This chip was quite popular in early CGA laptops (and MSX computers) and according to a datasheet it can handle multiple output modes: digital monochrome LCD, TTL RGB, analog RGB (for SCART connection) and color/mono composite. The problem is that the chroma pin on the chip is shared with signals required for LCD and wrong voltages/clocks on the pin could damage the LCD screen.

It looks like engineers wanted to have color composite output as there are missing parts on the logic board around these signal traces. However there was probably no business justification for having it in the laptop. Mobile users used the composite output mostly on the road when stayed at hotel (any hotel TV was better than the first generation of laptop LCDs).

I have found that Toshiba used monochrome TV outputs on their LCD CGA laptops as well (and IBM probably too). Since adding a color burst logic to the laptop would need heavy hardware modifications and some disassembling of BIOS I have to stay without a mobile device that could handle special multi-color (>4) CGA modes.

Kids Do Like History of Computers

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I’ve been pretty amazed that kids attending my computer class are aware of many historic moments in microcomputer history. At first they were scared when I told them that the lesson will be dedicated to history because they are used to the wrong style of teaching history through bullet points and dates. We talked about minis and micros and I’ve brought a lot of hardware from different eras of micro-computing.

It was nice to see that they were interested in historic hardware. They even play on 80s video game consoles at least using emulator software. This photo is from the end of a lesson about history of PC gaming (from beginning to 1996). Some kids were very interested how it is to play the first game from Need for Speed series.

My class is not about retro hardware but I’ve realized that using old computers is an effective and entertaining way to explain computer basics.

Lead-Acid Batteries

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We all have Lithium-based batteries in our mobile devices today. In mid-80s there was the first wave of battery-powered portable (IBM compatible) PCs. They used lead-acid batteries which are much heavier for the same charge capacity. There were a lot of troubles connected with these batteries. Average battery lifetime in a laptop was about one to two years before charge capacity degraded. If you discharged the battery too much or let the device unused for a longer time you had to replace the battery. You even had to unplug your device from wall power when the battery was full. Otherwise it can be damaged according to manufacturer’s instructions.

On the other side these batteries were (and are) cheaper than any other type suitable for large portable computers. These two were removed from my Bondwell Model-8 laptop. They are not specifically designed for the laptop so they can be easily replaced with new ones even today after 30 years. Similar ones are used in some devices such as emergency lights.