A friend of mine found this Olivetti M200 in a landfill and gave it to me as a gift. In this way, this magnificent computer was saved and became part of my collection.
When it arrived, the computer was in terrible condition: it was really dirty. Probably, it had been outdoors for some time, under the elements.
Cleaning the Olivetti M200
I have summarized in 4 minivideos all the disassembly and cleaning operations I carried out, as well as the final test of the vintage computer.
Olivetti M200
The Olivetti M200 (model BU 200-X) is a compact budget desktop, produced in 1988. The monitor (model DSM 200) is physically attached to the computer case. The computer that was given to me did not have a keyboard. To test it, I had to connect an AT keyboard with a 5-pin DIN connector. The Olivetti M200 computer is equipped with an NEC V40 processor (uPD70208), which is compatible with the Intel 80188, with a 16-bit architecture, but a data bus of only 8 bits. RAM has a capacity of 640 KB.
The stock operating system was MS DOS version 3.30, but it can be upgraded to later versions. Regarding data storage media, the Olivetti M200 is equipped with an internal 3.5″, 720KB floppy disk reader. It is possible to install a second floppy disk drive. There is a 20MB hard disk!
Internally, the motherboard is installed just below the monitor, at the level of the floppy disk drive. There are two cards in the lower case: one with the 8-bit ISA slots and one with the computer's external ports. Furthermore, the power supply and hard disk drive are present.
Startup screen
The computer starts with the Resident Diagnostics: they are diagnostic programs resident in ROM, which verify the correct functioning of the computer. Diagnostic programs check the operation of: CPU (Nec V40), ROM, DMA, Interrupts, RAM, Timer, Optional ROM, floppy disk drive and hard disk.
After the initial self test, the computer searches for a startup disk (floppy disk or hard disk). If there is no boot disk, it shows an error message: “BASIC Rom not available”.
Technical characteristics of the Olivetti M200
CPU: NEC V40 (μPD70208), 16 bit
RAM: 640 KB (the RAM banks are physically soldered onto the motherboard under the monitor)
ROM: contiene il POST = Power On Self Test e il BIOS = Basic Input-Output System
Graphics: Integrated CGA graphics card, monochrome monitor included in the computer
Text mode: 80 columns x 25 rows
Graphics mode: 640 x 200 pixels
Audio: beep
Keyboard: external AT with 5-pole DIN connector
Supplied software: MS DOS version 3.30
Storage media: No. 1 internal floppy disk drive, 3.5″, 720 KB, second optional floppy disk drive and No. 1 internal 20 MB hard disk
Expansion ports, internal:
- No. 2 ISA 8 bit expansion slots on separate card
- No. 2 connectors for 34-pin floppy disk drives
- 44-pin hard disk connector
- Connector for connection to other computer cards
- Integrated monitor connector
Expansion ports, external:
- Keyboard AT DIN 5 poles, sides
- Parallel (DB25)
- Serial (DB25)
Dimensions and weight: currently not measured
Emulation
The Olivetti M200 computer starts with the MS DOS operating system. It is possible to emulate the MS-DOS environment with DOSBox (although DOSBox is an emulator for x86 systems).
Power supply
The power supply of the Olivetti M200 personal computer is internal. On the back of the computer, there is the IEC C14 power connector, where you can connect the mains power cable. My example is powered by 230 V alternating current 50 Hz.
Inside there is a flat cable that carries voltage to the motherboard and a 4-pole Molex connector to power the hard disk.
The power switch is on the front. The monitor takes its 230V power directly from the computer via a rear cable.
Date of entry into the collection: 03/08/2024