IBM PS/2 Note N33 SX & N51 SX

The IBM PS/2 Note series was a line of notebooks from the PS/2 family announced in March 1992, half a year prior to the release of the first ThinkPad, the IBM ThinkPad 700. The notebooks were modeled after the PS/55 Note which was released by IBM in Japan in April 1991.

Background

After the departure of Bob Lawten from IBM, the team at IBM had little development direction after the IBM PS/2 L40 SX. James Cannavino pushed for the new notebook series, which fell behind schedule. During this time there was a distinction between notebooks and laptops, where the former are A4 sized and the latter are larger.

The PS/2 Model N33 SX (also known as PS/2 note N33 SX) was the first Western-released notebook-sized computer from IBM which was announced in 1991. This model was based on the AT-bus and had between 2 or 6MB RAM. It has a 9.5" 16-greyscale VGA LCD (640x480), external 1.44MB floppy connector, expansion ports and a 40MB or 80MB HDD, and weighs 5.5 lb (2.5 kg). There were two versions with one based on the original Japanese 12Mhz PS/55 Note and the other based on the Japanese 16Mhz N23 SX. The main two changes is that neither had internal floppy drives and they both had a Western keyboard.

External Resources & References

• Ardent Tool of Capitalism: PS/2 Model N33 SX (Type 8533) — Original system reference disks, deep-dive repairs, component pinouts, logic board layouts, and tech specs.

The PS/2 Note N51 SX (or PS/2 Model N51 SX) was a low-end mainstream notebook with the new MCA bus, which contained a slower version of the typical 386SX found in other notebooks. The N51 SX was delayed for months.

1. LCD Interface Connector
2. System-Expansion Port (120-pin)
3. Keyboard-Control Card Connector
4. Battery Presence Switch
5. LCD Interface Connector
6. LCD Interface Connector

1. I/O Panel Connector
2. Voltage Converter Connector
3. System Expansion Port (120-pin)
4. Password-Override Connector
5. Memory-Module Kit Connector
6. Hard-Disk Drive Connector
7. Voltage Converter Connector
8. Hard-Disk Drive Connector
9. Diskette-Drive Connector
10. Diskette-Drive Connector
11. I/O Panel Connector
12. I/O Panel Connector