Portables

Details: Published: 01 May 2025

In my quest to try and collect 'everything' IBM made which was portable, we have this strange curiosity - the IBM On-Line Note - model 5499-002. It's most notable 'claim to fame' is the fact one article from 1989 called this IBM's 'first' notebook computer - as in their first notebook-format computer WITH a battery. There was an earlier portable form factor machine called the 5535M (which was also developed by Ricoh but was completely different, bigger and looked a bit like an evolution of the IBM Convertible) - but that definitely wasn't notebook-sized and it didn't have a battery.

Read more: IBM On-Line Note -5499-002

Details: Published: 01 May 2025

IBM had a very long and troubled history in the development and release of portable machines. It's first machines were playing catchup to it's competitors, all of which existed within a space and time where the technology to enable a great mobile experience simply didn't exist.

For nearly a decade, IBM's portable machines were saddled with heavy displays which caused eye-strain, little or no battery life, lacklustre features and mind-numbing model names.

Read more: IBM Portables

Details: Published: 01 May 2025

N33 comes from the 8533 model type.

Note: this article is about the 16Mhz 386 model which was a direct relation to the Japan-only second-generation PS/55 Note - the N23 SX, minus the built-in floppy drive. It also had a Western keyboard and built-in external video display. The 12Mhz model without external video is completely different inside, made up of two main boards of equal size, whereas the 16Mhz model is one large board. The single planar motherboard is codenamed EXCEL-MAIN

The N33 machines are successors to the original note and N23 SX Japanese machines and is a precursor to the N51 and C23V Notes - which eventually became the C52 Thinkpad 700C.

Read more: PS/Note N33 SX Type 8533 (16Mhz)

Page 2 of 2

Latest Updates

IBM External Floppy Disk Drives

Due to the different IBM labs and companies developing IBM portables and the time period over which they existed before USB, there are a lot of different types of IBM floppy drive.

Whilst we're only covering external here, there are at least 3 types of connector:

26mm / fattest: Found on the 701c

21mm: Found on the PS/notes, 850, 7xx tablets. 360, 365

17mm / Thinnest: Found on the later models which favoured optical drives built-in such as the 755CD, 760, 600 and various 3xx series. Ultraslim floppy drive.

21mm

This early floppy drive 66G5069, also known as "UltraBay Diskette Drive enclosure" actually contains the original multibay floppy within it's large outer shell. There are also fixed standard external 21mm drives.

These ultrabay floppy drives came in various models from various manufacturers, so externally each 66G5069 drive may look the same, but internally it could be totally different.

TEAC FD-05HG

Here we have a TEAC FD-05HG drive, which has one eletrolytic cap, which as far as I know should only be replaced with an electrolytic. I have had drive read issues by replacing these with a solid capactor. It's a 100u / 10v capacitor seen below:

You can get away, like I did with a 7.7m through-hole capacitor with the legs splayed outwards:

Whilst it's open you may (or may not) want to clean the magnetic heads with a little IPA and check the corkscrew spindle which moves the heads forward and back across the diskette is moving smoothly.

Even though this 7.7mm tall capacitor is longer than the original surface mounted cap, it still just fits under the floppy drive chassis - although you cannot go any more than this.

Sony MPF720-2

And here is another 1.44Mb ultrabay floppy drive - the Sony MPF720-2 (weirdly suggesting it's a 720Kb drive, but it's a 1.44Mb drive):

This Sony drive is similar, but you do not need to remove the little PCB in order to replace the 47uf capacitor:

In this case, small 6mm through hole capacitors with the legs splade are a good replacement:

750 Series

I've managed to restore an almost complete set of the 750 series machines. Here are some of the collection:

Read more: 750 Series

Translating PS/55 note Japanese keyboard to English keyboard mapping

If you connect a western keyboard to the earliest PS/55 and PS/55 N23 SX notes, the keyboard mappings are all messed up. Here is a rough map of what key is mapped to what real keypress:

Read more: Translating PS/55 note Japanese keyboard to English keyboard mapping

IBM 5535 Multistation

IBM Japan had a range of Kanji-character-enabled desktop computers, called the Multistations. This was part of that family with the addition of a greyscale LCD display. Although 5535 is the 'laptop' range of machines, With the sheer size and weight (7kg), I think you would consider it more like a 'space saving desktop', much like the IBM Convertible. It has a sibling called the 5535-S which has a slightly different design and is 'less boxy'.

Read more: IBM 5535 Multistation

IBM PS/Note N45 SL (Zenith)

This is one of three N45 SL machines I have in a box. I previously gave up a day and ended up with one complete boxed one, a second unboxed one as a nice working companion and a third 'parts' machine. The N45 came in two models sporting different CPUs - the SL and SX.

You'll notice the case badge has similarities to both the 2141 (a PS/1 type) PS/note 182 and the PS/1 case badge - unlike the other PS/note and IBM Thinkpad oval badges, you'd think it is architecturally closely related to the (same year) PS/Note 182. However this machine feels Zenith-made through and through - much like the Thinkpad 300 which usurped it as the 2615. It shares a similar case plastic, power brick, display, keyboard and battery. Perhaps IBM were briefly marketing the N45 as the low-end (outsourced) notebook and the N51 as the high end (IBM-built) notebook, which eventually became the Thinkpad 300 as low-end and 700 as high.

Putting it another way, IBM were obviously toying with what to do about the cost-reduced 'low end' and had the 2141 "Lexmark Lexbook AR-10" PS/note and the Zenith-made N45 SL then "Zenith Z-Note 433Lnc+" 300 all coming out at once. You'll find some very reputable sites not even acknowledging the 2141 or 261x machines because they do not follow the 'true bloodline' of the IBM notebooks. The N45 SL may well have a Zenith step brother, but I haven't found a reference to it.

My first machine amazingly has a i387 upgrade chip (a maths coprocessor for the 386) fitted.

Read more: IBM PS/Note N45 SL (Zenith)