EEVblog #639 - IBM L40SX Retro Laptop Teardown

[EEVblog]

What strikes me about that laptop is how over-complicated it is. A (huge!) external switch mode power supply and tons of linear regulators on a fat heatsink?

One of those on the heatsink is a switchmode controller.

That odd (and doubtless costly) PLL board? All that 74 series logic glue? I know that state-of-the-art early 90s PC design was nowhere near as well-integrated as it was to become, and IBM never had a tradition of cost-reduction (quite the opposite), but I do wonder what the design criteria were.

Probably to reuse as many existing IBM stocked part numbers as possible. Also faster to market that way.

[richardkb]

Error code 161 dead battery and 163 date and time not set.

The 2 batteries were for CMOS settings and ram hold up when the system went into sleep/hibernation.

Early Toshiba laptops also had 2 sets of small battery packs.

Rich

[Stonent]

Oh and the 32bit issues on the old 386 processors didn't affect a lot of people initially because everyone was using windows 3.0 and 3.1.  32 bit instructions didn't come into play unless they were running OS/2. Windows 3.1 didn't use 32 bit instructions unless you enabled 32 bit enhanced mode manually which few people did and I don't think used the instructions that had the problems.

I enabled that on a lot of computers over the years and most everyone was like "My computer feels twice as fast!"

[SteveSmith]

The keyboard on that was sold by IBM as an external unit. They sold a couple of versions of it, some with built in TrackPoints, some without, and I believe ISO and ANSI layouts were available too.

Here's mine:

Much like the laptop, there was an external numeric keypad that you could get for that keyboard, too. Been hunting one of those for a long time now.

*Edit* Forgot to actually list the model number. That was the IBM Model M4-1 Space Saving Keyboard with Trackpoint.

[f4eru]

Hi Dave,

Why not ripping out the inside stuff, and put a modern motherboard, battery and screen ? would be ice to use the keyboard