Vienna 286: cleaning

It took me five hours to clean whole computer. I had to remove all components to properly clean the case, but It looks much better now. Anyway, the complete disassembly allowed me to take higher quality photos of all cards inside. I’ve never seen a standard desktop PC with so large mainboard – everything is done using many single-function chips instead of large multi-function chipsets (btw the missing chips are for an FDD controller).

Installed cards:

  • AST RAMvantage RAM card (supports up to 3 megs of XMS)
  • Western Digital WD1003A-WA2 HDD/FDD controller (connected to a ST-4038 hard drive)
  • GeniScan interface (for GeniScan hand scanners)
  • ATI Graphics Solution rev3 (the first ATI chip – supports Hercules and CGA)

Atari XL Design

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I like the clear aesthetic of the Atari XL series. These were the most visually appealing 8-bit home computers from the 80s. It’s sad that the design of newer Atari computers was much worse after Jack Tramiel came to the company.

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.